The Oakland Raiders overhauled their wide receiver unit on Thursday - with Jordy Nelson going in and Michael Crabtree going out. ESPN's Adam Schefter broke both stories:

Per Schefter, Nelson (33 this offseason), will receive a two-year contract worth $15 million, with $13 million guaranteed. Nelson was released by the Green Bay Packers on Tuesday, ending his 10-year stint with the franchise.

Crabtree - who turned 30 in September - is coming off his worst year since the 2013 season, when he was limited to five games. A two-time 1,000-yard receiver, Crabtree caught 58 passes for 618 yards and eight touchdowns.

The Raiders have begun making major changes since bringing back head coach Jon Gruden on a $100 million contract. Nelson joins an Oakland team that includes stars Derek Carr, Amari Cooper and Marshawn Lynch.

That being said, Nelson's age and decline in production is cause for concern, which is a reason why the Packers decided to cut their top receiver of the past decade. Nelson struggled in 2017 (thanks to Aaron Rodgers' broken collarbone, which forced him to miss more than half the season), catching just 53 passes for 482 yards and six touchdowns.

With most of this year's top free agent wide receivers off the market, Crabtree should generate plenty of interest across the league. At the age of 30 and coming off a down year, teams shouldn't have to pay too much for his services.

So it'll be interesting to see if Nelson will really be an upgrade over Crabtree. Both have excellent hands and work the middle of the field very well, but both are in their 30s and have had injury woes in the past.

We'll find out soon enough if Crabtree finds a new home. Considering that old rival Richard Sherman chose the San Francisco 49ers, it'd be sweet justice to see Crabtree head over to the Seattle Seahawks.

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