Crowder missed the final game last season with a right foot injury that left him on crutches, and he has been sidelined since Aug. 17 because of an unspecified leg injury.
The Dolphins sent Crowder for a second medical opinion Monday, coach Tony Sparano said. It's unclear whether the injury is related to last year's foot problem.
Sparano was noncommittal regarding the chances that Crowder will miss the regular-season opener Sept. 12 at Buffalo.
Tim Dobbins, acquired from San Diego in an offseason trade, has been filling in for Crowder at inside linebacker.
Copyright 2010 by The Associated Press