MARK O'Brien is a doubt for Derby County's game against Slavija Sarajevo tonight.
The central defender twisted an ankle in training yesterday and he was helped from the pitch.
His ankle was iced and strapped.
"Hopefully the injury is not too serious," said head coach Steve McClaren.
McClaren will utilise his squad for what is the second of two matches on the tour of Austria.
Derby lost 2-0 against Zenit St Petersburg on Tuesday and now face Slavija Sarajevo at the home of UFC Jennersdorf, who play in the Austrian Burgenlandliga.
The match kicks off at 6pm local time (5pm UK time).
The team will look different to the one that started against Zenit.
Richard Keogh, Jake Buxton, Craig Forsyth, Jeff Hendrick, Chris Martin and Simon Dawkins all played 90 minutes on Tuesday. Craig Bryson and Jamie Ward completed 71 minutes.
"What we wanted to do on this trip is to get 90 minutes into the players," said McClaren.
"We did that with a number of them on Tuesday while we worked the others very hard in training at the beginning of the week.
"This time we will give the others a game and work those who played Tuesday very hard in training.
"It means they all get the minutes on the pitch and the work they need."
McClaren said the young players who are with the first-team squad in Austria are likely to figure.
They are new signings Ivan Calero and Alban Bunjaku, as well as Jamie Hanson, Max Lowe and Farrend Rawson.