Middlesbrough have been left considering their options after trialist Nemanja Matic was forced to cut-short his stint on Teesside.
Boro came to agreement with his club MFK Kosice to come on trial for a week - but then the 20-year-old was handed a call-up to the full Serbia squad for their friendly with Poland on Sunday.
This has meant Matic spent just two-days at Boro's Rockcliffe Park training HQ.
Assistant manager Malcolm Crosby admits it has not easy for them to now make a proper assessment of Matic - who is being strongly linked with a permanent move to the club.
"Good luck to the boy on his call-up but it makes things difficult for us," he told the Evening Gazette.
"He looks a good footballer but he was only here for two days and it's very hard to make a judgement after such a short time.
"We've seen him in his league and he looks very good there, but with respect it's not the best of leagues and we needed to see how he shapes up against Premier League players.
"We've got time to think about it, but it could be at the end of the day that we have bigger priorities elsewhere next month."
Boro are also still considering Matic's team-mate Juraj Hovancik - who is also on trial with the club.