Leicester City's Aleksandar Tunchev may need further knee operation
The Bulgarian international has returned from Spain where he underwent the last of a series of injections to his knee in a bid to avoid another operation.
If the treatment – carried out by the specialist who treated him originally – works, Tunchev has a chance of playiing again this season.
But if it is unsuccessful, the 28-year-old will have to face another operation and Pearson said they did not want to wait too long and risk Tunchev's rehabilitation stretching into next season.
Tunchev ruptured his cruciate ligament at Crystal Palace in the third round of the FA Cup last January and made a brief return earlier this season.
But a further problem arose within the joint, which forced him to undergo another operation and has thwarted his efforts to make a first-team return.
Now Pearson is hoping the injection treatment will do the trick, but he accepts Tunchev's season could be over.
"He has had a course of injections and he has had his last one in Barcelona, so we will have to just wait and see how it goes," he said.
"It is a technique that is designed to avoid surgery. He has been better than we thought but we still don't know whether it will have the effect that we want.
"If you can avoid surgery you try to do that. Ultimately, we don't want to wait so long so that, if he needs surgery, it goes into the start of next season.
"The surgery that he may need, the recovery time is not quick.
"It is microfractures and it takes a while for that to heal because they actually drill into the bone, to make it bleed."
This allows for tissue to grow out through the holes and cover the bone, which in turn helps to heal and strengthen the joint.
Pearson added: "I have had it done twice myself so I know it can be a lengthy recovery process. It depends because every operation is different, but he may not need it.
"I am not going to put a time-frame on it. He is making reasonable progress, but whether he will be back or not this season is another thing."
The doubts over Tunchev were the main reason why Pearson swooped to sign defender Alex Bruce on loan from Ipswich Town for the rest of the season, and he is delighted to have the 25-year-old on board, although he admits he would have liked to have recruited more players during the transfer window.
"He has quite a bit of experience and it is an opportunity for him," said Pearson. "He gives us another player to provide competition.
"I think he has a point to prove and that can only help us, having people who are enthusiastic and driven to do well.
"He comes in at a time when we need fresh faces. It would have been nice to bring a few more in but, because of the financial situation, we haven't been able to do more business."
Aleksandar Tunchev
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