CINCINNATI -- One day after he was waived by the New Orleans Saints, linebacker Khairi Fortt was claimed off waivers by the Bengals on Tuesday, helping the team address a sudden need for help at the position, as well as on special teams.

Fortt will take the roster spot that had been held by linebacker Sean Porter, who suffered a season-ending knee injury on the opening kickoff in Sunday night's 43-17 loss at New England. Porter had just returned from a hamstring injury that had him sidelined since the preseason. The Bengals placed Porter on their season-ending injured reserve Tuesday.

Fortt comes to Cincinnati after the Saints inexplicably let go of him Monday. Previous to his release, the rookie seemed to be in the Saints' good graces. After all, they used a fourth-round pick on him during May's draft, and they tabbed him as their short-term IR player. Since teams are only allowed to have one player placed under the IR's to-return designation per season, it made little sense for New Orleans to let go of him. The Saints can no longer put a player on short-term IR.

Fortt's release from the Saints was not related to any violation of league rules or legal issues, a league source told ESPN Saints reporter Mike Triplett.

"There's a little uncertainty to where he is at just in regards to the amount of snaps he had or was limited to based on the injury," Saints coach Sean Payton said when the team put Fortt on the short-term IR in the preseason. "We think he has a chance to develop into a good young player and yet it is still kind of an incomplete, if you will, in regards to the evaluation. The [IR] rule varies. It is only our second year with it. How use it is one element you didn't have two years ago, three years ago."

A 6-foot-2, 240-pound player from Cal, Fortt appeared in the preseason, recording one tackle and one defended pass before suffering an unspecified leg injury in the second preseason game. He would have been eligible to practice for the Saints after their Week 6 game, and allowed to play after Week 8.

Bengals officials are working under the presumption that since Fortt was released by the Saints that he cleared their physical and is healed enough to play. Once a player gets released, his previous injury-list designations end for that reason. He'll undergo a physical when he arrives in Cincinnati, but he should be cleared Wednesday when the Bengals resume practice ahead of their Week 6 game against the Panthers.

The Bengals also have used their short-term IR designation. Tight end Tyler Eifert (dislocated elbow) is expected back Nov. 6 when the Bengals host Cleveland on a Thursday night. Along with Porter, the Bengals also have placed rookie offensive lineman Trey Hopkins (leg), tight end Alex Smith (biceps) and linebacker J.K. Schaffer (concussion) on their season-ending IR lists.

Injuries have derailed Porter's time with the Bengals. He missed all of last season because of them, and has struggled to get on the field this year because of them. The former fourth-round pick from Texas A&M said earlier this year that he had never missed time due to injury until his pro career started last spring.

ESPN Saints reporter Mike Triplett contributed to this report.