Bryant, who was traded to the Raiders for a third-round pick, had asked to be traded out of Pittsburgh in September only to change his mind. He recorded 50 receptions for 603 yards and three touchdowns last season and added a scoring catch in the team's 45-42 playoff loss to the Jacksonville Jaguars.
"When I heard about Martavis, I was like 'Oh, man.' I really enjoyed playing with Martavis," Roethlisberger said, per the Pittsburgh Post-Gazette. "I think he was a great weapon, he helped our offense, did some great things by attracting attention and making plays for us.
"I was kind of caught off guard, but teams have reasons for doing things. I think part of it was him expressing trade things that we all heard so much about. I think he's probably pretty happy. For him and his family, if you're in a good happy place, then good for him."
While the Steelers lost one receiver, they welcomed another in James Washington. The second-round pick joins Antonio Brown and JuJu Smith-Schuster in providing weapons with which Roethlisberger can attack the defense.
Roethlisberger played in every game in 2017 until sitting out the regular-season finale and earned his sixth Pro Bowl selection, throwing for 4,251 yards with 28 touchdowns versus 14 interceptions. He also became the first quarterback in history with three 500-yard games.