Lewis told Pittsburgh reporters on a conference call Wednesday that he exchanged messages this week with Roethlisberger, who regrets he can't play in a game that could decide the AFC North leader.
"He wishes he were out there -- he wishes he were out there, man," Lewis said. "It's a respect thing we have playing against each other. It's a rivalry but, once again, it goes back to the level of respect we have."
Roethlisberger's four-game suspension for violating the NFL's personal conduct policy doesn't end until next week.
While the Ravens (2-1) and Steelers (3-0) have one of the NFL's strongest rivalries, Lewis said he sent Roethlisberger text messages of encouragement while the league was weighing last spring whether to discipline the quarterback. Roethlisberger was suspended following accusations that he sexually assaulted a Georgia college student, although no charges were filed.
"We texted each other when he was going through what he was going through," Lewis said. "I was there for him. It's more of a brotherhood. The game will always take care of itself on the field, but off the field if we don't look out for each other, nobody else will."
Lewis, one of the league's most accomplished players, said he exchanges text messages with numerous other NFL players.
"We always hit [text] each other," Lewis said. "There are many people I hit, just simple stuff."
Lewis has had off-field issues. He was charged with murder after leading Baltimore to a Super Bowl victory in 2000, but the charges were dropped after Lewis agreed to testify against two other men. He subsequently pleaded guilty to a misdemeanor charge of obstruction of justice. He also was fined $250,000 by NFL.
Relating to his own experiences, Lewis said he advised Roethlisberger to quickly put his problems behind him.
"If you're trying to please the world, you're going to confuse yourself," Lewis said. "If you're going to worry about what people say about you, you're going to confuse yourself. All you can do is move on, live on. ... Don't let nobody pull you back into it, don't let nobody make you keep talking about it. Once it's done, it's done."
Roethlisberger also has talked with and exchanged messages with teammates, including Hines Ward, while suspended. But he is not permitted to discuss team issues. He has been training with a quarterback coach, throwing to receivers and working out to remain in game shape.
He has not played since a Sept. 2 preseason game against Carolina, and cannot play again until Oct. 17 against Cleveland. The Steelers don't play next week, but Roethlisberger can resume practicing then.