Isak was taken off at halftime of their preseason defeat to Yokohama F Marinos.
But Howe told Chronicle Live: "No, that was scheduled for him. Of course he went over on his shoulder early in the game, it was sore but he was fine to carry on. We don’t envisage any problems but of course we need to check out the mechanism and how his shoulder is but I think he looks OK.
"I don’t know if it's more than one or two of them (being an injury away from a crisis), I think it’s more one!
"But yeah of course, whenever you’re going through a pre-season, I think you are always two or three injuries away from any one position looking light.
"We’ll be very pleased to get our full compliment back, Anthony Gordon and Kieran Trippier and then we can work the whole squad together. It has felt fractured in different ways, there’s a lot of first minutes in pre-season for some players and I think that showed today in our performance."