The Oakland Raiders have unfortunately not had the type of offseason that they would have liked so far. While the team has signed some solid players in free agency, they haven't brought in the multiple stars they hoped to. With most of the marquee names locked up already, here are a few free agent fits that are left.

Running back: Adrian Peterson

Peterson is not a free agent and the Raiders have already signed Trent Richardson. But that doesn't mean Oakland has given up on adding the MVP-winning running back.

"As for Peterson, the only way he could be had is through a trade," ESPN Raiders reporter Bill Williamson wrote. "The Raiders have the money to bring on Peterson's contract, but the competition may be difficult."

Receiver: Michael Crabtree

The list of available receivers includes Greg Jennings, Hakeem Nicks and Wes Welker. Crabtree is the youngest of that group and although he is coming off a down season, he'd likely be the best fit in Oakland.

Tight end: Jermaine Gresham

Gresham is reportedly undergoing back surgery, meaning he will not provide an immediate impact. But he could be a solid addition when healthier for a team that got just 58 catches for 534 yards and four touchdowns out of its starting tight end.  

Defensive end: Jarvis Jenkins

Edge-rushers still on the market include Anthony Spencer, Dwight Freeney and Osi Umenyiora. However, Jenkins is significantly younger than all of them. Even though he never put it all together in Washington, the former second-round pick still has some upside.