Coach Tony Dungy said Mungro had a "loose body" removed from the knee. He said the Colts would know more about Mungro next week.
The team has a bye this weekend.
The Colts (5-1) also might be without running back Ricky Williams after the bye week. Williams, who started the last three games as Edgerrin James sat out with a back injury, has a sprained left ankle and is expected to miss two weeks.
Defensive lineman Chad Bratzke has a chip fracture in his right forearm, but Dungy said he is expected to play against the Texans.