ALAMEDA The Raiders admitted to a $6.5 million mistake Monday.
Matt Flynn, acquired in April to be Oakland's starting quarterback, was released after losing the job to Terrelle Pryor.
"I don't know exactly what the reason was; it just didn't work," coach Dennis Allen said. "Terrelle came in here and took over the job. He's earned the position he's in. We just felt it was in our best interest to move on from that."
Monday's move completes the transaction with Seattle. The Seahawks get the Raiders' fifth-round draft pick in 2014, and with Flynn off Oakland's roster, a conditional 2015 pick is erased.
The release of Flynn is even more costly because general manager Reggie McKenzie restructured the quarterback's contract to fit under the salary cap, guaranteeing him $6.5 million in 2013.
Last week, Flynn was demoted to third string behind undrafted free-agent rookie Matt McGloin.
Flynn signed with Seattle as a free agent last year and also was projected to be the Seahawks' starting quarterback, but he lost the job to rookie Russell Wilson. He will collect more than $14 million from the Seahawks and Raiders despite making only one start.
The saving grace for Mc-Kenzie, who was not available for comment, is the presence of Pryor. The improvement of the last pick made by Al Davis in the 2011 supplemental draft has been as remarkable as Flynn's play has been abysmal.
Sunday night's 27-17 victory over San Diego was another Pryor revelation. He completed 18 of 23 passes for 221 yards and two touchdowns with no turnovers. His 135.7 passer rating was the highest by a Raider since Rich Gannon had a 138.9 in Week 3 of his MVP season in 2002.
"He's probably leaps and bounds better than we thought he'd be at this point in time," Allen said.
Flynn played his way out of the starting lineup at the end of the exhibition season, partly because of elbow tendinitis but mostly because of increasingly shaky play.
The Raiders were content to let him be the backup, as Seattle did the year before. That was until Flynn started against Washington on Sept. 29 when Pryor experienced symptoms from a concussion the previous week and things went awry.
With the help of a blocked punt for a touchdown and a Flynn touchdown pass, the Raiders took a 14-0 lead. Flynn then had an interception returned for a touchdown, couldn't move the ball and lost two fumbles, and the Raiders lost 24-14.
"When Flynn got another opportunity last week and wasn't able to deliver, I think they just weren't willing to deal with it," safety Charles Woodson said in a Sirius XM radio appearance. "It just kind of mounted up against him, and it didn't work out."
It didn't help that Flynn wasn't putting the best face on his demotion. Asked two games into the season if Flynn was the same helpful teammate he'd been in the quarterback room as the starter, Pryor said, "I can't really worry about or think about whether guys are still dwelling on stuff. I've got a job to do, and my butt's on the line."