NASHVILLE, Tenn. -- As bad as things have been for the Titans offensive line this season, the team could say it was building some continuity.

Four-fifths of the line has started every game this season, with Taylor Lewan taking over at left tackle for the injured Michael Roos after five games.

Now the team will undergo a second lineup change. Brian Schwenke tore the MCL in his left knee Sunday in Philadelphia and has been placed on injured-reserve. Chris Spencer is in line to take over as the starting center.

The Titans signed veteran interior lineman Eric Olsen for depth. Olsen signed with Tennessee during the offseason and he was with the team through camp.

Lewan might also be out. Jim Wyatt of The Tennessean says the sprained ankle that knocked Lewan out against the Eagles is a high ankle sprain. Those usually take a while to recover from. Byron Stingily would fill in if Lewan is sidelined.

The offensive line has remained an issue for the Titans this season, though they spent a second consecutive first-round pick on a lineman (Lewan was the 11th overall pick) and gave a big free-agent deal to right tackle Michael Oher.

Schwenke wasn’t great, but he’s an inexpensive piece with promise who played between a high-pried free agent from 2012 (Andy Levitre) and an underachieving No. 1 pick from 2013 (Chance Warmack).

Levitre’s spot is in jeopardy beyond this season and the team can get out of Oher’s deal for no money beyond the $6 million it will have paid him in 2014.