"We've had him scanned and it's better than we thought," said Coppell.
"He'll be out for four weeks at most."
Graeme Murty is approaching fitness.
Royals physio Jon Fearn told the club's website www.readingfc.co.uk: "He is looking a lot better and we're hoping he'll be back training soon.
"He wasn't quite 100% for Everton but the extra few days will take him up a level."