If tests Monday confirm those fears, Long's season will be over. An MRI is scheduled for Monday, but one source told Darlington, "It doesn't look good."
Long is a free agent after the season, and if he can't play again this season, there's an outside chance he could have taken his last snap as a Dolphin.
Long, the No. 1 overall pick in the 2008 NFL Draft, hasn't played well this season, but we'd guess the Dolphins still could use their franchise tag on him. They can take a look at how Jonathan Martin, normally Miami's right tackle, would fare on the left side in the meantime.
Follow Gregg Rosenthal on Twitter @greggrosenthal.