Linebacker Bryan Thomas, the longest-tenured player on the Jets, will have an MRI exam Monday afternoon to determine the extent of damage to a pectoral muscle, a source said.

If the test shows a tear, Thomas, 33, will be lost for the final three games -- and possibly for good. He was injured in Sunday's 17-10 win over the Jaguars.

Thomas underwent Achilles-tendon and shoulder surgery last season, returning to the Jets on a one-year contract. The former first-round pick provides experience and stability to the linebacking corps and has played well in recent weeks. Before Sunday's game, he had 29 tackles and 2.5 sacks.