Posted by ESPN.com's James Walker
Keisel, 30, is among several notable players who were set to become free agents after this season. But the Steelers are taking the route of keeping together the team that won last season's Super Bowl.
In addition to Keisel, linebacker James Harrison, receiver Hines Ward and tight end Heath Miller were among the players who received sizable contract extensions before the start of the regular season.
In other roster moves, the Steelers place offensive guard Darnell Stapleton on injured reserve and released four players to get under Tuesday's 75-player limit. The four players cut were receiver Martin Nance, safety Derrick Richardson, center Alex Stepanovich and receiver Steven Black.