Albion announced on Monday they had reached an agreement to re-sign Yokuslu – who impressed on loan for the club last year – following his release from Celta Vigo.
The Turkish international has put pen to paper on a three year deal at The Hawthorns.
But he is still waiting for his work permit to arrive to allow him entry into the UK.
And that means he hasn’t undergone a full pre-season with the 28-year-old having not featured in any friendlies.
“It’s an exciting signing for us because he played very well when he was here before,” Bruce said when asked if Yokuslu will be fit for the season opener on July 30.
“But we’re going to have to see where he is fitness-wise. There is a difference between being fit and being match-fit.
“Has he been playing? When you miss pre-season, I always think it’s very difficult to play catch up.
“But I believe he is a wonderful pro and a good athlete and will do everything he can to be right.
“It’s a really good signing for us and I think all the signings we have made so far will certainly help us.”
Meanwhile, Bruce said he wouldn’t have any concerns playing Adam Reach at left-back next season.
The 29-year-old was deployed in the role at Oxford on Tuesday.
“Reachy is a great pro,” Bruce added. “His best position is wide but he has played as one of a three in midfield.
“He can play as full-back, wing-back.
“He is never going to let you down, no chance.”