Callum Davidson admits the loss of key midfielder David Wotherspoon for the remainder of the season is a huge blow for struggling St Johnstone

The 31-year-old has been sidelined since having to go off early in the Premier Sports Cup semi-final defeat by Celtic. Scans have now confirmed that he has suffered anterior cruciate ligament damage and will not play again this term.

Manager Davidson said: “He’s a huge player for us to lose. For me, he was one of our best players last season, so to lose him for the rest of the season is a huge blow for us. It’s up to others now to step up and get a place in that team.”

Davidson believes Wotherspoon has the required mentality to fight back strongly from his setback.

He said: “He’s fine. He’s got his head round where he is with his injury. He’s a sensible lad. He realises where he is injury-wise. I’ve had a few injuries myself and I think sometimes when you know what your injury is and how long it’s going to be, it can be easier than having an unknown injury. He’s got his head screwed on.”

Injuries to Wotherspoon and other midfielders prompted Davidson to dip into the free-agent market and sign former Derby player Jacob Butterfield this week. The 31-year-old is in line to make his debut away to cinch Premiership leaders Rangers on Wednesday.

Davidson said: “Jacob is experienced and he’s kept himself really fit. He’s looked good in training. Midfield is an area where we’ve been a bit short so it’s an area where we’ve needed a bit more strength in depth.”

Saints find themselves heading to Ibrox rock-bottom of the cinch Premiership towards the end of a year in which they won a domestic cup double.

Davidson said: “I don’t really like looking at the league position but it is top against bottom and nobody will give us a chance.

“In these type of games we always seem to perform well, so hopefully we get a good performance. Rangers have got top quality players. In the first 15 minutes against Hearts they were superb on the attacking side and that’s something we’ve got to stop.”

Davidson is confident Saints can turn the tide after a challenging first half to the campaign.

He said: “The Hibs game, when we were 1-0 up and then lost after having a man sent off, was probably the low point for me this season and obviously the raft of injuries has been a test.

“But I see the squad sticking together and staying strong, and that gives me belief and positivity that the group are ready and willing to fight all the way to the end of the season. I always try to be positive and I believe the group I’ve got here will come through.”