Reading are to be without Tom McIntyre and Dom Ballard for this evening's visit of Carlisle United.
Back from the international break on the weekend, the Royals picked up their first away win for over 370 days at Wycombe Wanderers, a 2-1 victory at Adams Park.
25-year-old McIntyre has been missing since September and is likely to miss at least another few weeks after having a scan.
"Tom had a scan this week," Selles said before the trip to Wycombe. "We expected him to come back in the next two weeks to train with us but the scan shows that it is a bit slower than we expected in healing. He will take between three and four weeks.
"The situation with him has been really unfortunate, starting with a concussion against Burton Albion and coming back and getting an injury in the first minutes of training out of nowhere. It is much better to not risk anything on that and have him fully fit when he needs to be than risking a reappearance."
Ballard went down in the first half against the Chairboys on Saturday and is unlikely to play for the club again.
Speaking after the win in Buckinghamshire, Ruben Selles said: "It didn’t look great. it was after the shot that he made. He felt something strange. He is going to the hospital to take a scan. We don’t have the verdict yet but it doesn’t look well."
Paul Mukariu, Ballard's replacement, signalled to come off with five minutes to go.
Despite fears of an injury, Selles believes it is 'nothing to worry about' as the Cumbrians make their first visit to Berkshire for over 40 years.
The likes of Ben Elliott, Caylan Vickers and Harlee Dean all missed out on the matchday squad on Saturday, leaving them fresh for possible involvement this evening.
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