While Bamba has lost his place in the starting eleven recently, the popular centre-back has been a regular on the bench.
But Bamba was missing from the Leeds squad at Griffin Park and Evans revealed a personal issue had come up which meant the defender needed to head back to France.
The Leeds head coach told LUTV: "I've had to let Sol return to France. The big fella has a family matter that he has to deal with.
"All our thoughts are with the big man today and we're looking forward to having our captain back in the next couple of days", Evans added.
Evans also revealed that he was close to handing a full Leeds debut to Toumani Diagouraga.
Diagouraga was signed up from Brentford on Monday, but was only on the Leeds bench despite much speculation he would start against his former club.
"Of course he was close [to starting].
"He's a good signing for us, but we never really got him on the training ground until Monday for obvious reasons", Evans concluded.