Bellamy eventually moved to West Ham over the summer and Koumas said: "Craig suffered with the rotation policy last year.
"I spoke to him a lot about it, and it was tough for him because he is one of those players who needs to play week in week out to get his form going.
"But it didn't really happen for him at Liverpool."
Koumas finds it difficult to understand Benitez at times, adding: "When you have a settled 11 that's winning games, it's hard to change things.
"If you asked our gaffer (Chris Hutchings) what he would do after winning three or four on the bounce...how could you change it?"