The Leeds head coach has been discussing the summer signing.
Indeed, the 24-year-old missed a big chance against Fulham on Tuesday night and Evans has highlighted a problem many 'seem to forget' about the winger.
He has pointed out the fact Dallas didn't start a high percentage of his games with Brentford last season, meaning he isn't used to the constant action he has been given at Leeds this time around.
Evans told reporters: "I think what people seem to forget with Stuart is that he only had 18 or 19 starts last season at Brentford, with the rest coming off the bench.
"He's come and been involved in practically every game. Sometimes that can catch you. He's got a huge desire but there's been a little bit [of a lack of] freshness."
Dallas has certainly been one of Leeds' best performers this season but has perhaps slowed down a little of late, while his miss was notable against Fulham.
The 24-year-old should bounce back without a problem, although Evans' point stands that fatigue could catch up with the winger.
Should he start at Brighton on Monday night, it will present another tough test for the Northern Irishman - but the same applies for the Leeds side as a whole.