The two reportedly had a strained relationship during their six years together in Pittsburgh, which ended last week after the Steelers elected against renewing Haley's contract.
"We had a great run, very successful when he was here," Roethlisberger told NFL Network's Jane Slater on Wednesday. "Just thankful for the opportunity I had to play with him and be a part of that offense, and now we have to face him twice a year. So we'll see how that goes."
Randy Fichtner, who served as Pittsburgh's quarterbacks coach, replaced Haley and reportedly has a good relationship with Roethlisberger.
Communication between Haley and Roethlisberger worsened during this past season and is one of the reasons why Fichtner was moved from the coaches booth to the sideline, the NFL Network reported. The move was reportedly Roethlisberger's idea, backed up by coach Mike Tomlin.
Haley, on Wednesday, became the first offensive coordinator under Browns head coach Hue Jackson, who is 1-31 in two seasons while calling the plays in Cleveland.
"This is a great opportunity," the 50-year-old Haley said. "The Browns have a great history, great fans and deserve to have some fun and experience some winning. I want to help be part of that process. There is obviously a lot of work to do in order to get there, but I've always been excited about facing a challenge. There is no better feeling than when you can be a part of turning an organization around.
"Hue and I have had some good battles in competing against each other as coordinators and even as a head coach. We know each other well and I have a great deal of respect for him. He's so competitive and winning is the only thing that's important to him. You want to work with a coach like that. Hue and I share a lot of similar beliefs on how to be successful on offense."
Haley goes from a Steelers' team that made four straight playoff appearances to a club that went 0-16 in 2017 and 1-15 in 2016. He also exits an offense that finished eighth in the NFL with 25.4 points per game to one that finished 32nd with 14.6 points per contest.