Aberdeen forward Scott Wright could be sidelined for the remainder of the season after injuring his knee in training on Monday.
The 22-year old, who has featured seven times for the Pittodrie side this season, has suffered suspected cruciate ligament damage.
Wright, who made his debut in 2014, is under contract until 2021.
"With nobody near him, he went over, got his studs caught in the turf," explained manager Derek McInnes.
"We first thought it was only going to be cartilage damage, but on further investigation it looks like there is damage to the cruciate. We will get that confirmed next week when the specialist sees it.
"If that is the case, it is just tragic for Scott, and really disappointing for us."
McInnes revealed that he got news of Wright's injury while watching winger Connor McLennan come off the bench to score a late winning double for the Scotland Under-21s against Croatia.
"You have got the highs, which is probably football in a nutshell, of Connor, then the disappointment with the news that we weren't expecting to be honest on Scott," he said.
McLennan has been restricted to just four Dons outings this season and his manager hopes the winger's international heroics can have a positive spin-off at Pittodrie.
"He is feeling good about himself which can maybe kick start his season," he said. "He has had wee knocks here and there, injuries here and there. He had an operation in the summer.
"Hopefully he uses this as a catalyst to go and kick on now for us, because he is a player who I have got a high regard for and I do think he is a player who is capable of cementing a first team spot here on a regular basis."
Dons aim to keep May quiet
Aberdeen, who have Shay Logan and Dean Campbell fit again, are looking to build on an impressive 3-0 victory over Ross County when they host St Johnstone on Saturday.
It means a swift Pittodrie return for striker Stevie May, who recently returned for a second spell with the Perth side after a disappointing couple of seasons with the Dons.
"I don't think Stevie has got a point to prove in terms of his effort," said McInnes. "The goal return we were probably looking for more, and Stevie was probably looking for more.
"Stevie is a boy who I have no doubt has potential and the capabilities to do well again at St Johnstone and we do wish him well.
"Clearly we want to make sure we try and keep him quiet on Saturday. There are other attacking threats in the St Johnstone team, they have got good options in the wider areas, so we know we have got a job to get the clean sheet that we got against Ross County."