T.J. Waldburger has been removed from a scheduled UFC 161 bout with Sean Pierson. Kenny Robertson, however, has already agreed to take his place.
UFC officials announced the switch Thursday evening, but neglected to reveal the reason for Waldburger's removal.
Pierson (13-6) was on the verge of seeing his UFC dreams dashed after winning his Octagon debut, but then losing his next two bouts. He is currently on a two-fight winning streak, but injuries have kept him from fighting since he defeated Lance Benoist at UFC 152 last September.
Robertson (12-2) has also had a rocky UFC career.
He was one and done, losing to Mike Pierce in 2011. Robertson then went outside the promotion to get back on the winning track. He returned as a late replacement for Jon Fitch at UFC on Fuel TV 4, but lost a decision to Aaron Simpson. He got another shot at UFC 157 and finished Brock Jardine with a kneebar.
UFC interim bantamweight champion Renan Barão and Eddie Wineland headline UFC 161 on June 15. It marks the promotion's first trip to Winnipeg, Manitoba, Canada.