The Seattle Seahawks have acquired running back Marshawn Lynch in a trade, multiple sources have confirmed. The trade was first reported by Jay Glazer of FOX Sports, who stated Seattle will give up a fourth-round pick in the 2011 draft and a conditional pick in 2012.

"We've been interested in Marshawn for a long time," coach Pete Carroll said after Seattle's practice Tuesday.

Seattle released Julius Jones to make room for Lynch on Seattle's roster.

Lynch is a former first-round pick out of California where he played with Justin Forsett, now the Seahawks starting running back. The two remain close as Lynch attended Forsett's wedding this offseason.

Lynch rushed for more than 1,000 yards each of his first two seasons in the league, but lost his starting job last season to Fred Jackson. This year, the Bills drafted C.J. Spiller in the first round.

Lynch had been mentioned as a potential target of Seattle going back before the draft, but the Bills' asking price was too high for the Seahawks, who instead chose to trade for Leon Washington and LenDale White.

The Seahawks are acquiring Lynch to jumpstart a rushing attack that continues to lag. Seattle is averaging 79.5 yards per game, which ranks No. 27 in the 32-team league.

"We bring a guy into the program that we think is going to give us a little boost," Carroll said. "We've emphasized trying to get this running game in order. We hope that he'll help us in that regard."

At 24, Lynch is still relatively young and someone who has experience rushing in a zone-blocking system while in college. He is a player the Seahawks have pursued repeatedly, seeking to acquire him from the Bills, and now at 0-4, Buffalo was ready to part with him.

Carroll was asked if Lynch becomes Seattle's starter at tailback.

"We're going to bring him in to play a lot," Carroll said. "We'll wait and see when we get him here, but we're bringing him in here to play a bunch."

Forsett is Seattle's starter, but the team has gone nine games without having a running back rush for a touchdown. Forsett said he was not concerned about opportunitieshe might lose because of Lynch's arrival.

"Coach definitely stresses competition," Forsett said. "Me and Marshawn have worked well together in the past so I definitely have no issue with that."

Lynch is signed through the 2012 season.

Seattle also formally announced it re-signed Chester Pitts on Tuesday, waiving Evan Dietrich-Smith to make room on the roster.