Roethlisberger's start streak may end at 30 due to ankle injury

Slowed by a sprained ankle and still nursing a sore right shoulder, starting quarterback Ben Roethlisberger missed a second straight day of practice on Thursday, and Pittsburgh Steelers officials are likely to take a cautionary approach and sit the four-year veteran for Sunday's season finale at Baltimore.

Roethlisberger, who on Thursday was named as the AFC offensive player of the week for his performance in a Dec. 20 victory at St. Louis, has started all 15 games this season and 30 straight games over two years. He is one of only 12 quarterbacks in the league who have started every game for their respective teams.

If Roethlisberger does not play, 10-year veteran Charlie Batch would get his first start of the year. Batch has not started a game since the 2006 season opener, when Roethlisberger was recovering from an appendectomy. Batch has played sparingly in 2007, and completed just one of five passes for 14 yards.

The Steelers have clinched the AFC North division and it will be difficult for the team to improve on its No. 4 seed in the AFC playoff bracket. Pittsburgh needs a victory over the Ravens and an Oakland upset of San Diego to become the No. 3 seed.

Despite what has been a career season, one in which Roethlisberger earned his first Pro Bowl berth, the Steelers' star has had a difficult year in some ways. He has been sacked 47 times, including 24 times in the past six outings, and has been forced to scramble frequently behind a suspect offensive line.

Even in a disappointing year, the Baltimore defense, which sacked Roethlisberger 14 times in two meetings in 2006 and three times in the teams' first matchup this year, can still rush the passer.

Pittsburgh coaches would prefer to have Roethlisberger as close to 100 percent as possible for the first-round playoff game, which likely will pit the Steelers against the Jacksonville Jaguars. The Jags defeated the Steelers at Heinz Field on Dec. 16 and sacked Roethlisberger five times.

For the season, Roethlisberger has completed 264 of 404 passes for 3,154 yards, with 32 touchdown passes and only 11 interceptions. The 32 touchdown passes are a franchise record, and Roethlisberger's career-best passer rating of 104.4 is the second best in the NFL heading into the final week of the season.

Pittsburgh coaches and players have great faith in Batch, a former starter for the Detroit Lions, and a knowledgeable veteran with 49 starts on his resume.

In a matter relating to the offensive line, starting left tackle Marvel Smith, the Steelers' best pass protector, but a player who has missed three starts this season, underwent Thursday surgery to address a disk problem that has plagued him all season and affected his play. Pittsburgh will wait to make a determination on whether to place Smith on injured reserve.

There is a chance, the Steelers believe, that the eight-year veteran and former Pro Bowl performer might be able to return to the lineup if the team advances to the second round of the playoffs.

The Steelers' second-round pick in the 2000 draft, Smith has appeared in 106 games, with 103 starts, during his eight seasons with the club. Fourth-year veteran Max Starks, who has replaced Smith in the lineup for the three games that he missed earlier in the year, will take over at left tackle. Starks was a two-year starter at right tackle before losing that job to Willie Colon in training camp.

Senior writer Len Pasquarelli covers the NFL for ESPN.com.