Lewan got into the lineup after five games when Michael Roos was lost for the season with a knee injury.
Michael Oher (toe) recently had a second opinion, and Ken Whisenhunt said the Titans and their right tackle are still sorting things. He remains out.
Oher's backup, Byron Stingily, was limited Thursday with his own ankle injury.
Will Svitek has been overmatched while subbing the last two weeks for Lewan. Terren Jones played against the New York Giants after less than a week with the team. Journeyman Jamon Meredith was just brought in -- the Titans' seventh tackle this season.
"I don't know what it is, I don't know why it happens at that one position, especially the tackles," coach Ken Whisenhunt said. "On the O-line in general, it's been pretty tough. Five or six months ago when we drafted Taylor, everybody was like, 'Why did you draft him? You've got tackles.' And all of a sudden he's played and now he's down and we've gone through three or four other guys. It's been crazy."
In 2012, the Titans were hard hit by injuries on the offensive line late in the season. In a blowout loss at Green Bay in their second-to-last game of the year, they started three marginal-to-poor fill-ins: Mitch Petrus, Deuce Lutui and Stingily.
That spurred a determination by the Titans to upgrade and get deeper.
Two big free agents, two first-round draft picks and a mid-round draft pick later, the Titans are in a familiar situation.