"It is disappointing for the club, he [Keane] has had five good years here where he has scored a lot of goals and has been brilliant for the club," Bent told Sky Sports News.
"We can't stand on ceremony and we have got to move forward."
Bent is hopeful he will get the chance to replace Keane in Juande Ramos' starting line-up.
"Hopefully [I will get the chance], obviously a player like Robbie needs replacing but if I am called upon and the gaffer gives me the nod, I will give it a go," he said.
"He [Ramos] hasn't said anything [about Keane], what has happened with Robbie is down to him and the club, he didn't say anything to the players and we just have to get on with it.
"He [Keane] was a big figure in the dressing room, a nice guy and a top man, but obviously as I said we have to keep moving forward and push on in the league."