In a move that significantly bolsters the depth chart, but also serves as a tacit admission that starter Brian Griese will miss extensive playing time and possibly the rest of the 2005 season, the Tampa Bay Buccaneers on Tuesday acquired quarterback Tim Rattay from the San Francisco 49ers. The deal came just before the NFL's trade deadline of 4 p.m. ET, and after Tampa Bay officials had auditioned a few veteran free-agent quarterbacks earlier in the day. The 49ers, who have turned the starting job over to rookie Alex Smith, the top overall selection in this year's draft, will get a pick in the 2006 draft as compensation. Rattay, 28, started the first four games of this season for the 49ers before coach Mike Nolan made the move to Smith two weeks ago. There were rumors at the time that the 49ers would entertain trade offers for Rattay, a sixth-year veteran, after the switch. San Francisco did not get many inquiries about Rattay, though, until the Bucs decided to make a move on him. One of the few teams in the league to have carried four quarterbacks on the roster at the outset of the season, the 49ers still have veterans Ken Dorsey and Cody Pickett to back up Smith. Clearly, though, the departure of Rattay signals that San Francisco plans to go with Smith as the starter for the rest of the season, and that he essentially has no competition for the starting job. Removing Rattay from the equation should allow Smith to function without looking over his shoulder, and to know the job is his to keep now. The move also reflects the concern of Bucs officials over a knee injury that sources insist will sideline Griese the rest of the season. ESPN's Chris Mortensen reported Monday that Griese is believed to have suffered tears to the anterior cruciate ligament and medial collateral ligament when he was hit by Miami linebacker Zach Thomas in Sunday's victory over the Dolphins. "We're getting some more analysis," general manager Bruce Allen said. "He's still on the team. He is wanting to play. We're hopeful that he can. But we're going to get the proper medical opinion." In the absence of Griese, who had started all six games this season, the Bucs will turn to three-year veteran Chris Simms, who has experienced an up-and-down relationship with head coach Jon Gruden. The Tampa Bay roster also includes Luke McCown, obtained from Cleveland in a trade this summer. Certainly, given that it will take some time for Rattay to assimilate the Bucs offense, Simms will be the starter for the foreseeable future. But Gruden, who loves to collect quarterbacks and who most people around the league assumed would make a move after the injury to Griese, will try to accelerate Rattay's learning curve to provide the Bucs another veteran option if Simms falters. "We feel he'll be a great fit for our team," Allen said. "He'll come in and be our No. 3 quarterback. It gives us some great insurance and a feeling that we can sleep at night that we have a bona fide NFL starter." In six years in the league, Rattay, a seventh-round choice in the 2000 draft, has appeared in 32 games and started 16 contests, including nine starts last season. He has completed 356 of 586 passes for 3,941 yards, with 24 touchdown passes, 18 interceptions and an efficiency rating of 81.6. In his four starts this season, Rattay had a 70.3 rating, with 56 completions in 97 passes for 667 yards, with five touchdown passes and six interceptions.