Charlie Frye on IR after wrist surgery, Cable says its a 4-5 month rehab.

The Oakland Raiders signed free-agent quarterback Kyle Boller to undisclosed terms Thursday, one day after Bruce Gradkowski tore a pectoral muscle while lifting weights.

Gradkowski will undergo surgery for the injury Friday, but he's expected to be fully healed by the start of training camp in July, his agent, Ralph Cindrich, confirmed in an e-mail.

The addition of Boller gives the Raiders three healthy quarterbacks on their roster entering the upcoming minicamp and OTAs, with former No. 1 overall pick Jamarcus Russell and Charlie Frye.

When Raiders coach Tom Cable addressed the full team for a year-end wrap-up Monday, two of those quarterbacks weren’t in attendance.

Charlie Frye was getting an MRI exam for what is believed to be a lower back strain. And Jamarcus Russell? He had an excused absence for “personal issues.”

Cable declined to state what those issues are. And though they may have been perfectly valid, even unavoidable, it was yet another red flag in the file of a young quarterback who is shaping up to be one of the great underperformers in NFL history. Russell, a former No.1 overall draft choice who started the first nine games before giving way to journeyman Bruce Gradkowski, finished the season with a passer rating of 50.0. It was the NFL’s worst for a qualifying quarterback since three of them — San Diego’s Craig Whelihan and Ryan Leaf, and Philadelphia’s Bobby Hoying — came in below 50 in 1998.

Quarterback Charlie Frye has been replaced by Jamarcus Russell at the start of the third quarter for the Oakland Raiders.

Frye has an injured back and ankle and his return is questionable. He is riding an exercise bike on the sideline. Frye threw for 180 yards and a touchdown in the first half. Oakland trailed Baltimore 14-10 at the break in a game the Ravens needed to win to make the playoffs.

Russell was booed when he entered the game.

Raiders QB Bruce Gradkowski (knees) did not practice Wednesday. Charlie Frye will get the start again this week.

Raiders QB Charlie Frye will start at quarterback against the Ravens in the season finale this Sunday, and both he and coach Tom Cable are hoping he plays a little more like Charlie Frye this time.

Cable began his news conference with a requisite reliving of Sunday's 23-9 loss in Cleveland, then said he expected Charlie Frye to start at quarterback again when Baltimore visits the Coliseum in the season finale Sunday.

If Jamarcus Russell has something to prove, he probably won't get a chance until next season. Cable and the Raiders can't sacrifice the meager dignity of finishing at 6-10, which would be the team's best record since 2002, to the lost cause of cultivating a No. 1 draft pick who did little but regress when he held the starting job.

"I think this is a big game for this team," Cable said, "and as I said when I made this switch (away from Russell) initially, (it gives) us the best chance to win."

Asked whether the Raiders would be playoff-bound if they had received an average or better performance from their quarterback, Cable quietly and succinctly made the strongest statement of the afternoon: "Without even asking that question, you know that we would have."

Raiders QB Charlie Frye (concussion probable) is expected to get the start this week, but you shouldn't be considering him for fantasy purposes.

Raiders QB Charlie Frye (concussion) took reps Thursday.

Quarterback Charlie Frye and tight end Zach Miller went through warmups and drills, were wearing helmets and looked to be joining practice when team sessions started Wedesday.

That would indicate both men have been cleared following concussions _ Miller missed the Denver game _ and are free of symptoms. With Bruce Gradkowski not at practice, Frye is the probable starter against the Browns Sunday.

Frye was going through drills along with Jamarcus Russell and J.p. Losman, while newly-signed practice squad player Jeff Otis went through special teams drills.

Those not at practice included DE Greg Ellis (knee), RB Justin Fargas (knee), wide receiver Darrius Heyward-bey (foot), tight end Brandon Myers (concussion) and wide receiver/return specialist Nick Miller (tibia).

Ellis said last week he would probably not be practicing until Friday over the final two weeks of the season.