National Football League history would be different as we know it if some deals that were in the works had actually gone through involving some of the biggest names in the league.
Regardless of how great some players were, their respective teams always considered wheeling and dealing when needing to make a change. In some cases, major trades were just about completed before one side got cold feet and pulled out.
In other cases, teams were thought to be close or even a lock to sign a player in free agency, however things didn't work out for whatever reason, changing the course of league history.
For some teams, it's the moves they make that put them over the top. For others, the deals they don't make can cripple the franchise for years to come. Hindsight is always 20/20, but some of the teams on this list just made horrible decisions when given a chance to land an all-time great player.
It's astounding to see the level of quarterbacks that were once up for grabs. In this day and age, it's unthinkable for a team to trade a top quarterback. Back in the day, it almost happened more than most people realize.
Just imagine if Dan Marino had been traded to the Oakland Raiders or John Elway to the Washington Redskins. Both of those deals almost happened and who knows what it would have meant for each player's career.
Let's take a look at some of the biggest deals - whether in free agency or through trades - that almost happened but never did.
15 49ers Trade Jim Harbaugh to Browns
While head coaches being traded in sports are rare, the Niners nearly dealt head coach Jim Harbaugh to the Cleveland Browns in 2014. Harbaugh had fallen out of favor with ownership in San Fran and the team was looking to get some compensation before Harbaugh inevitably left.
So the Browns had a deal on the table that would have compensated the Niners with multiple draft picks in exchange for Harbaugh. Before the deal could get done, Harbaugh decided to stay with the Niners instead of going to the Browns and coaching a team in the same division as his brother, Ravens head coach John Harbaugh.
Harbaugh, who was considered one of the league's best coaches at the time, would have been a great addition to a Browns franchise desperately needing a new direction and some credibility. Harbaugh ultimately left the Niners and decided to go to Michigan, where he is still the head coach today.
14 Broncos Sign Bruce Smith
Before re-upping with the Buffalo Bills in 1989, superstar defensive end Bruce Smith signed a five-year, $7.5 million offer sheet with the Broncos. Because he was a restricted free agent, any offer Smith agreed to could be matched by the Bills and he would be forced to stay with the only team he had known until that point.
The Bills wisely decided to match the Broncos' offer and Smith remained in Buffalo. Smith spent the next 11 years of his career with the Bills after signing that deal, compiling 126.5 sacks on his way to a Hall of Fame career and legendary status in Bills history. Smith played in all four Super Bowl losses the Bills suffered in the early 1990s.
Smith moved on from the Bills in 2000 when he signed with the Redskins, spending the last four years of his career in Washington. Sadly for Smith, had he joined the 'Skins in 1989 he would have won a Super Bowl in the 1991 season, something he was unable to accomplish in Buffalo.
13 49ers Sign Lance Briggs
Another lifelong member of one team, linebacker Lance Briggs nearly went to San Francisco in 2008. The problem for the Niners was they were talking to Briggs before the time period in which teams are allowed to talk to prospective free agents, thus resulting in tampering charges from the NFL. San Fran was stripped of its fifth-round pick for the violation and was also forced to swap third-round picks with the Bears.
Briggs ended up back in Chicago and the Niners finished 7-9. We can only dream of a linebacker combo that could have consisted of Briggs, Patrick Willis, and later Navorro Bowman. Briggs and the Niners flirted with each other once again in 2015, however he later decided to retire after dealing with injuries in the two seasons prior.
12 Redskins Trade Albert Haynesworth Back to Titans
Albert Haynesworth left the Tennessee Titans in free agency in 2009 to sign with the Washington Redskins on a massive seven-year, $100 million deal. After playing below expectations in his first season in 2009, Haynesworth came to camp overweight and failed multiple conditioning tests in 2010. The word was that Haynesworth did this all by design so he could be released and not have to do anything for the guaranteed money in his contract.
Before his 2010 demise in Washington, the Titans were actively trying to trade for Haynesworth and bring their former star player back on at least two different occasions. Fortunately for the Titans, the asking price by the Redskins was too high for the team's liking and Tennessee never pulled the trigger. It isn't clear if Haynesworth would have changed once back in Tennessee, but chances are he would have been a bum no matter where he played with his attitude.
11 Rams Trade Orlando Pace to the Texans
When you think Orlando Pace, you think St. Louis Rams and the Greatest Show on Turf. Pace was a huge part of a great offensive line that dominated opposing defenses for the Rams' two Super Bowl runs, one of which ended with a victory.
In the years that followed, Pace was almost dealt to the Houston Texans. In the midst of contract negotiations where the Rams and Pace couldn't come to terms for years, St. Louis thought about dealing the Pro Bowl offensive tackle to the Texans. The deal never happened because the Texans weren't willing to give up what the Rams wanted, which was two first-round picks.
Pace ended up getting his money in a seven-year, $52.8 million deal. After playing in every game in 2005, Pace was slowed by injuries the next two seasons, playing in just nine games. His final season in St. Louis was in 2008 and he finished his career as a member of the Chicago Bears in 2009. If the Texans had acquired Pace, maybe the team could have protected former No. 1 overall pick David Carr better, who was sacked relentlessly during his failed stint in Houston.
10 Redskins Trade Darrell Green to the Broncos
Hall of Fame cornerback Darrell Green did something few players in the league ever do nowadays: he played 20 seasons with the same team, the Redskins.
That almost didn't happen, though. In 1989 the Redskins were in talks to trade Green to the Broncos in exchange for the team's No. 1 pick and wide receiver Mark Jackson. When asked if he would deal Jackson, then-head coach Dan Reeves said "hell no" and explained a trade wasn't likely because he wasn't willing to give up what the Redskins were asking for.
Reeves also hinted he was uncomfortable with Green's contract demands, which were in the neighborhood of $1 million per year. From there things broke down and the trade never happened, which led to Green remaining in Washington for the rest of his career.
9 Hafthor Bjornsson Signs with Colts
HBO's "Game of Thrones" has been a television phenomenon for years now and is set to embark on its seventh season. For fans of the show, Hafthor Bjornsson is better known by his character name Ser Gregor "The Mountain" Clegane. The name "The Mountain" does him justice as the former Europe's Strongest Man winner stands at 6-foot-9 and weighs 419 pounds.
That kind of size on an NFL field intrigued Indianapolis Colts owner Jim Irsay, who hinted that his general manager should sign the big actor. Just imagine how big of a deal that would have been for both the NFL and fans of the show. It would have had major cross appeal and likely would have brought new viewers in to watch Colts games. Despite Irsay's interest, a deal never materialized and Bjornsson stuck to his day job.
8 Peyton Manning Signs with 49ers
The San Francisco 49ers were the other team who had a good shot to land Manning in 2012. Coming off a season in which the team made it to the NFC Championship game and lost to the New York Giants, Manning was the perfect piece to put the Niners over the top. Then-head coach Jim Harbaugh was looking for more than just a game-manager, which is what quarterback Alex Smith was for the Niners.
Manning not only visited the Niners, but he reportedly had a physical and worked out for San Fran. Still, that wasn't enough to land Manning and he instead chose the Broncos. The Niners did OK for themselves in the years that followed with two more trips to the NFC Championship game, including an unsuccessful attempt at a Super Bowl win against the Ravens. Adding Manning to the roster could have led to a Niners dynasty.
7 49ers Trade Terrell Owens to Ravens
Wide receiver Terrell Owens was supposed to be a free agent after the 2003 season, however his agent screwed up the paperwork and missed the deadline for him to void his contract with the San Francisco 49ers. Seeing an opportunity to capitalize on a player who was clearly intending to leave, the Niners dealt Owens to the Baltimore Ravens for a second-round pick.
Owens already had his heart set on playing for the Philadelphia Eagles and refused to join the Ravens in any capacity, including not showing up for his physical. Instead, Owens filed a grievance to become a free agent because of the money he stood to make and was later involved in a three-team deal that sent him to Philly as part of a compromise. The Ravens got their second-round pick back from the Niners and a fourth-round pick from the Eagles. The Niners also received defensive end Brandon Whiting from Philly.
Owens paid dividends immediately, as he was a key player in the Eagles' trip to the Super Bowl in his first season. He quickly wore out his welcome in 2005 and was released by the team in 2006.
6 Dolphins Trade Dan Marino to the Raiders
When you look at Dan Marino's incredible Hall of Fame career, you couldn't imagine the Miami Dolphins ever wanting to trade him. Well, think again, as the Dolphins nearly traded one of the great quarterbacks in NFL history to the then-Los Angeles Raiders in 1990 after suffering a fourth consecutive season without making the playoffs.
The deal almost went through between the Dolphins and Raiders, but Shula nixed it at the last minute and asked for more from the Raiders. It must have been a pretty hefty raise in asking price because owner Al Davis decided it wasn't for him.
What a shame for football fans that this didn't happening considering Marino would have played with running backs Marcus Allen and Bo Jackson, as well as wide receiver Tim Brown. That just might have been Marino's ticket to the Super Bowl ring he never got during his career.
5 Reggie White Signs with Redskins
When Reggie White became a free agent in 1993, the Redskins were one of the finalists to sign the defensive end. With a free-spending owner and a mutual interest from White, it looked like Washington was going to snag White from Green Bay. However, that same free-spending owner, Jack Kent Cooke, was unwilling to go higher than four years for $13 million after the Packers had a four-year, $16 million deal on the table for White.
Cooke didn't believe in spending that much on a 31-year-old defensive lineman, so the signing never happened. White ended up getting four years and $17 million from the Packers in a front-loaded deal that blew away the competition. Not only is he now in the Hall of Fame, but White also went on to win Super Bowl XXXI with the Packers in the final year of his deal. It's doubtful he could've helped the Redskins much, though, with the team going 13-35 over the next three seasons.
4 Saints Trade Archie Manning to Packers
In 1974, Archie Manning almost became a Packer. Green Bay was desperate to find a quarterback and had actually reached a deal with the New Orleans Saints to acquire Manning for a pair of first- and second-round picks. The story goes the 25-year-old quarterback had a terrible game the week prior and the Saints were planning on going to their backup, Bobby Scott, making Manning expendable.
Scott ended up suffering a knee injury and the Saints' other quarterback, Larry Cipa, stunk it up in place of Scott. With no other options behind center, the Saints decided they needed to keep Manning and pulled out of the deal with the Packers. Green Bay had no choice but to send five picks to the Los Angeles Rams for John Hadl, who was no Archie Manning. The Packers would finish with a losing record that season and didn't see the playoffs again until 1982. Meanwhile, Manning's career was OK but never really took off, mostly due to an perennially horrible team around him that never finished with a winning record during his tenure in New Orleans.
3 Broncos Trade John Elway to Redskins
Prior to the Washington Redskins' 1991 Super Bowl-winning season, former general manager Charlie Casserly asked the Broncos if John Elway was available for trade. The Broncos were actually somewhat open to it and said their price would be tackle Jim Lachey. Washington was unwilling to part ways with Lachey and the Broncos later nixed any possibility that Elway would be dealt once their demands weren't met.
Of course, things worked out just fine for the Redskins as the team went on to win the Super Bowl later that season and Redskins quarterback Mark Rypien actually won the game's MVP. Elway didn't do too bad himself after going on to win two consecutive Super Bowls, sending him off into the sunset as a winner once he retired following the 1998 campaign.
2 Peyton Manning Signs with Cardinals
Before Peyton Manning ultimately decided to sign with the Denver Broncos in 2012, he strongly considered two other teams, with one of them being the Arizona Cardinals. Manning went as far as to visit Arizona - one of the few places he did visit - and took a tour of the team's training facility. He also met the team's owner and top executives, as well as went over film and discussed the Cardinals' roster and salary cap situation.
Seems like Manning was doing his homework extensively and there was a real consideration on the part of the future Hall of Fame quarterback, with some reports even suggesting the Cardinals were one of the favorites to sign him at one point. Sadly for the Cardinals, Manning chose the Broncos and went on to play in two Super Bowls, winning one. It easily could have been the Cardinals in that situation had Manning signed in Arizona.
1 Packers Trade Aaron Rodgers to Raiders
It's bad enough the Oakland Raiders passed on Aaron Rodgers in the 2005 draft when they took cornerback Fabian Washington one pick before the Packers signal-caller, but the team also had a chance to trade for the superstar quarterback.
With the Packers looking for a playmaker, the team inquired about star wide receiver Randy Moss, who was made available by the Raiders after he became disgruntled. So, before the 2007 season, the Packers reportedly tried to offer Rodgers and a seventh-round pick to the Raiders for Moss in order to pair him with then-starting quarterback, Brett Favre.
Needless to say the trade never happened and Moss was instead dealt to the New England Patriots where he amassed 1,493 yards and 23 touchdowns in his first season. Rodgers is now a lock for Canton and a Super Bowl winner, while the Raiders went through a slew of quarterbacks before Derek Carr finally emerged as a star in 2016.