Third-year receiver Brandon Lloyd had an MRI exam and missed practice. Lloyd leads the 49ers with 19 receptions for 369 yards and three touchdowns. He had experienced soreness in his lower back and hip and said the test revealed a left quadriceps strain. Lloyd was added to San Francisco's injury report as probable and is expected to return to practice Friday.

Ken Dorsey was among the last players off the San Francisco 49ers' practice field Wednesday, a bag of footballs slung over his sweaty shoulder following his usual post-practice throwing session. Even though Dorsey probably will start for the 49ers on Sunday in place of injured rookie Alex Smith, the recent third-string quarterback is sticking to his routine of extra work and additional preparation. Smith, the No. 1 overall draft pick, has two strained ligaments in his right knee -- and Tim Rattay, the early season starter and recent backup, will be on the opposite sideline as a backup for the Tampa Bay Buccaneers, who acquired him in a trade last week.

Alex Smith sprained his right knee in San Francisco's fifth straight loss, and the 49ers aren't certain their rookie franchise quarterback will play against Tampa Bay on Sunday. Smith, 8-of-16 for 92 yards and one interception in the Niners' humiliating 52-17 defeat, was hurt when his cleats got caught in the turf while LaVar Arrington tackled him in the first quarter. He played the rest of the game, feeling only momentary pain -- but after his knee stiffened up overnight, the No. 1 overall draft pick wore a heavy wrap and a brace Monday at the 49ers' training complex. He is listed as probable on the injury report, but the 49ers will wait until later in the week to determine whether Smith can make his third career start. Smith sprained two ligaments on the inside of his knee, and fluid built up behind his kneecap. Though he had previous back injuries from weightlifting, he had never been hurt while playing football in high school or at Utah. ``I guess that's why I do things like that,'' Smith said, referring to his dangerous attempt to make a play while Arrington was bearing down on him. ``Other people would have gone out of bounds or gone down. Obviously, I need to learn from that.''

Tim Rattay was acquired Tuesday by Tampa Bay as the Buccaneers addressed their shortage at quarterback after Brian Griese injured his knee. The Bucs sent an undisclosed draft choice to the San Francisco 49ers for the six-year veteran, who lost his job in San Francisco after four weeks to top overall draft pick Alex Smith. The transaction beat the NFL trading deadline of 4 p.m. Tuesday. To make room for Rattay on the active roster, the Bucs released rookie fullback Rick Razzano. Griese tore knee ligaments in Sunday's victory over Miami and will be out for a lengthy time. Chris Simms took over for Griese as the Buccaneers beat the Dolphins 27-13. Rattay, a seventh-round pick in 2000, started nine games last season and beat out Smith in training camp this season. But he performed poorly after an opening victory over St. Louis and was benched by coach Mike Nolan.

Linebacker Jeff Ulbrich tore his bicep muscle Sunday trying to make a tackle on Colts' running back Edgerrin James. "After I made the tackle, I looked down and my bicep was rolled up and off to one side," Ulbrich told the San Francisco Chronicle. Ulbrich now has to decide whether to have season-ending surgery or play through the pain.

The San Francisco 49ers on Thursday agreed to a trade that will send former starting linebacker Jamie Winborn, estranged from the team for the past week, to the Jacksonville Jaguars, ESPN.com confirmed. The deal is contingent upon Winborn, 26, passing a physical examination. The fifth-year veteran arrived in Jacksonville late Thursday night and the physical will be administered on Friday morning. Terms of the trade were not yet available, but it is believed the 49ers will receive a 2006 draft choice. "It's exciting," Winborn said when reached on his cell phone. "It's a new start for me."

Overall No. 1 draft pick Alex Smith was promoted to be the San Francisco 49ers' starting quarterback on Tuesday, ascending to the job after just four games as Tim Rattay's backup. Smith will make his first NFL start on Sunday against Peyton Manning and the Indianapolis Colts at Candlestick Park. The former Utah star played in two of the 49ers' first four games, mopping up in losses to Philadelphia and Arizona. ``I feel that Alex gives us the best chance to win, and I believe he's ready,'' San Francisco coach Mike Nolan said. ``Tim has handled everything very well, but at this time in the process, I believe it's time to get Alex in the game. ... At 1-3, we didn't draft Alex to just sit him on the bench. At 1-3, I believe we need to begin to utilize him.''

Coach Mike Nolan is desperate to snap the San Francisco 49ers out of their offensive funk, and he's wondering whether the solution is the $49 million man holding a clipboard on the sideline. After the 49ers' offense sputtered to another meager performance in a 31-14 loss to the Arizona Cardinals in Mexico City, Nolan said he hadn't decided whether veteran Tim Rattay or No. 1 draft pick Alex Smith would be his starting quarterback for Sunday's game against Indianapolis. ``We're still in the evaluation process,'' Nolan said Monday when asked to name a starter. ``I'm going to give myself a little more time on that. ... There's a right way to do things, and I'm always going to do it the right way.''

Even before the first snap, commissioner Paul Tagliabue declared the NFL's first regular-season game outside the United States a rousing success -- and a prelude to the sport's future. Tagliabue believes the San Francisco 49ers' meeting with the Arizona Cardinals in Mexico City will be the first venture in an annual extravaganza, with at least one festive regular-season game on foreign soil every season. The commissioner's ability to convince each NFL club to take turns giving up a home game for the cause seems to be the main obstacle to his ambitious plan to boost American football's international popularity. But Tagliabue is confident the owners will see the long-term benefits of such a plan, which could be discussed at league meetings this month. "The key is to let them know well in advance that they're going to be giving up a home game," Tagliabue said. "The other key is to make (giving up a game) a universal obligation to be a member of the NFL."