Ben Roethlisberger and Antonio Brown used to be one of the NFL’s most dominant duos.

Now, they aren't even friends.

The former Steelers teammates had a falling-out at the end of the 2018 season when Roethlisberger criticized Brown's route-running.

The criticism fractured their relationship, and eventually, Brown was traded to the Raiders.

"I wish I wouldn't have done it," Roethlisberger told NBC Sports' Michele Tafoya on Sunday Night Football.

Pressed further, Roethlisberger explained why he regrets what he said about Brown.

"Because we saw what happened, and obviously, it ruined a friendship," Roethlisberger said. "I just got caught up in the heat of the battle."

Brown wasn't the only Steelers wide receiver whom Roethlisberger criticized during that radio interview. He called out James Washington, but the 2018 second-round draft pick appreciated the honest words, according to the quarterback.

Why couldn't Brown handle the criticism like Washington?

"You'll have to ask him," Roethlisberger said. "I'm not sure."

[RELATED: Brown finds 'happy ending' on helmet issue]

Despite the demise of their friendship, Roethlisberger still wants Brown to succeed with his new team, telling Tafoya that he hopes the Raiders receiver "has a good, healthy season."