The forward has a toe injury that is still limiting him, even though he is fully fit to play.
The Sweden striker has been struggling with the problem this season and was unable to score in their 1-0 loss to Brighton.
Howe stated: "I think there are reasons for that. Any kind of injury breaks momentum and I think to expect Alex to have been at his very best today... (would be asking a lot).
"Of course, yes he trained in the build-up to the game, but he hadn't had the depth of training he probably needs for full performance. But I thought a lot of his game was very good today. I have no major issues and I thought he played very well out of possession for us.
"Anthony (Gordon), I thought, led the line really well in that respect. I think if he had scored two goals, no-one could have complained and we'd be having a different conversation, so they are such fine margins for any player."