The striker has joined Wolves on-loan.
Howe told the Daily Echo: “I always want my players to go and do well. I respect Benik a lot.
“Letting him go was a decision I didn't really want to make but the player felt he needed football so it was something I reluctantly agreed to.
“He was keen to play and I think part of that was that he was keen to score and do well. You always want players to want to achieve individually, that has to be there. Sometimes you have to make them understand their opportunity will come and they have to be patient and develop behind the scenes. Sometimes they have to wait behind players performing very well ahead of them.
“But sometimes it's very difficult to convince players of that if they don't see an opportunity coming and I think Benik was in that situation."
Asked if he expected Grabban to seek a permanent move to a new club in the summer, Howe said: “I think that's a possibility but never say never. I would never shut the door on anybody.
“Let's see how he does at Aston Villa. It's a great club and a great opportunity for him to achieve something historic, so we wish him well.
“I'd leave the door open for anybody but especially a player like Grabbs given how well he has done for me historically."