Walsall midfielder Joe Edwards will miss at least the rest of the season after damaging knee ligaments in Saturday's defeat against Blackburn.
The 27-year-old, who is out of contract with the League One side in the summer, will see a specialist on Friday.
Manager Jon Whitney said: "We will know more after that but he is definitely out for the season and probably the start of next season.
"It's a devastating blow for him especially and also for us as a group."
The Saddlers are only five points clear of the relegation zone after surrendering a lead to go down 2-1 against Peterborough at London Road on Tuesday night.
Meanwhile, Walsall's League One match at home to high-flying Wigan Athletic has been rearranged for Wednesday 21 March (19:45 GMT).
The game was originally scheduled for Saturday 17 March but has had to be put back due to the Latics' FA Cup quarter-final commitments.