It was expected that the Finland international would move to Bundesliga club Hanover, following three years with injury problems.
Bruce said: “Is Mikael in with a chance of playing against Chelsea? Absolutely.
“There is no question of that. He has looked so sharp this pre-season.
“We really hope he can stay that way, that his knee is fixed and he is pain free which wasn’t the case at the end of the season.
“No-one needs to tell me how good a player Mikael is when on song and fit. It was a fantastic effort when he scored 19 goals, 17 of them in the Premiership, three or four seasons ago.
“If he stays fit, it will be like having a new signing and I might not have to go looking for another striker to sign.
“There was talk about him moving to Germany and maybe we thought the change of club would do him good after battling injuries for three years.
“But the deal never happened – thankfully – and he has been showing what we all know he is capable of.
“If Mikael is back to his best for good, no-one deserves it more because he has shown great resilience and determination through all the low times and never thrown the towel in.
“He’s done all the pre-season and you can see his confidence slowly but surely returning.”
