The Blues have drawn each of their last four Premier League fixtures, edging them into fifth spot in the Premier League table.
"It's been difficult for him," Bowen told the Manchester Evening News. "Ade was flying at the start of the season, for the first four or five games, and then had a suspension and an international break, which meant he missed a few games.
"He has also had a few niggling little injuries, so hasn't had a lot of actual day-to-day training. We work on intensity when we train outside, and he has missed that. His last couple of games have been about trying to patch him up and sling him back on to the field of play.
"He is really positive when he goes out there but it's not the same when you have missed training days. It has affected him going into games - he has had a mental thing about maybe not being 100 per cent. But this week he seems to be pain-free and hopefully will be 100 per cent for the weekend (against Burnley)."