St Mirren defender Alex Iacovitti will be out of action until Christmas.
The centre-back - signed in the summer - has been ruled out for three months through a hamstring tendon injury suffered in a bounce match during the international break.
The injury leaves Stephen Robinson light in defensive options with other natural left-sided option Richard Taylor playing through a hernia issue which will require surgery at a later date.
"Alex Iacovitti last Friday in a practice game got a tendon injury that's probably going to be until Christmas, which is a big blow for us," said Robinson.
"It's a hamstring tendon injury that can be quite hard to rehab. But he's got the best person I know [physio Gerry Docherty] in terms of getting him back. But we're probably looking at Christmas time before that happens again.
"We've got Richard Taylor, who has been playing through a hernia operation on the left side of defence. It is an issue for us going forward. Richard's hernia, you can play through them for a certain amount of time, but it's a ticking time bomb.
"It's something that's a concern for us at this moment in time in terms of that left-sided centre-half position.
"It's one of those things that happens in football, it's just the timing of it. We knew Richard was carrying this injury. We knew it would only be a matter of time before he needed to be operated on.
"Alex was that perfect replacement to come in. So that's an issue for me at the minute that I'm currently looking at."
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Robinson could be forced into the transfer market for a short-term free agent pick-up to resolve the injury crisis with Charles Dunne a possible option having spent pre-season in Paisley after his contract expired at the end of last season.
"We may have to bring somebody in on a short term basis," said the St Mirren manager. "But I'll speak to the board about that and see where we go.
"There aren't many free agents out there. There's not many within our price range. We've spent our budget. So it would be a case of a very short term deal to try and get us through if we need to do that."
Pushed on a return for Dunne, he said: "I think that's a little bit of a coincidence. Charles has been training with us throughout the pre-season.
"He's done pre-season with us because he was waiting to go abroad. That move I don't think has happened or is happening at this moment in time.
"Charles has turned down numerous SPFL clubs and English clubs because of his desire to go abroad. So that is a little bit of a coincidence.
"But it may be an option. We'll see. It hasn't been discussed at this stage but as I say, these injuries have only just happened."
Despite the hernia issue, Taylor could feature against Kilmarnock on Saturday with the player and club hoping to postpone surgery until a later date with more options available.
Whenever Taylor does go under the knife, a three to four week layoff would follow meaning an international break may be an optimal time.
"You could reduce it down to three or four games," said Robinson of plans for Taylor having surgery. "And that's why any kind of signing that we would make would be a very short term basis."
St Mirren do have some good news on the injury front, though, with Greg Kiltie and James Scott back in training and Killian Phillips not unavailable long-term despite a bug while on international duty.
Robinson said: "Greg Kiltie's joined back in training again fully. James Scott's joined back in fully.
"Killian Phillips had a bit of a bug and didn't do anything with the international squad or play any minutes and didn't do a lot of training. So, whether he's involved tomorrow, we'll have a look at his training stats."
