The 21-year-old has been an important addition to manager Leroy Rosenior's squad, since coming on loan to Plainmoor from Division Two high-flyers Bristol City.
Clist has played two matches in pain following an accidental clash in training with the Devon outfit.
The injury means the youngster will miss the next two to three weeks, which means that Clist is likely not to feature for Rosenior's squad again, unless the club reach the Division Three play-offs.
The Gulls occupy the last play-off berth in the table by a single point, with four league matches remaining in the season.
