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.