Next football season, Ray Lewis will be on the sideline, perhaps saving up his pregame speeches — motivational, to be sure, but sometimes indecipherable in their ferocity — for his son’s first season at the University of Miami. The latest news, notes and analysis of the N.F.L. playoffs. Go to The Fifth Down Blog . N.F.L. Live Scoreboard Standings Stats | Injuries Giants Schedule/Results Stats | Roster Depth Chart Jets Schedule/Results Stats | Roster Depth Chart It is almost impossible to imagine the N.F.L. without Lewis, without the eyeblack streaked across his face, without his wild dances as he emerged from the stadium tunnel, without his punishing hits. In truth, Lewis’s play has been ebbing for a few years, his ability to run sideline to sideline slowed by age, his intimidating tackles weakened by the loss of weight he shed to try to regain some speed. Even when he tore his triceps this season and missed the final 10 games of the regular season, it was clear that the Baltimore Ravens more desperately missed a teammate, linebacker Terrell Suggs, who was out part of the season with an Achilles’ tear. But when Lewis announced Wednesday that he would retire after this season — the Ravens play the Indianapolis Colts in a wild-card game Sunday — it felt like the end of an era, one that Lewis dominated as the greatest linebacker of his generation and perhaps the greatest middle linebacker in N.F.L. history. He said it was “time to create a new legacy.” “I talked to my team today,” Lewis said to reporters. “I talked to them about life in general. And everything that starts has an end. For me, today, I told my team that this will be my last ride.” Lewis will play Sunday for the first time since he tore his triceps in mid-October. Because the Ravens are the fourth seed, the game is likely to be his last one in Baltimore, the city where he has spent his entire N.F.L. career. Lewis joined the team in 1996 as a first-round draft pick — though not the first linebacker taken that year — out of Miami, the same year the Ravens started playing in Baltimore after Art Modell moved the franchise from Cleveland. Lewis brought immediate attention and relevance to the Ravens. In 2000, a year after he was indicted on murder charges after a fight broke out at a Super Bowl party — he later pleaded guilty to a lesser charge and served no time in prison — Lewis was the league’s defensive player of the year for the first of two times and the most valuable player of the Super Bowl, which the Ravens won. Lewis also crafted a defensive legacy that still defines and shapes the perception of the team. In 2000, Baltimore gave up the fewest points in a 16-game season, allowing it to overcome a five-game stretch in which the offense did not score a touchdown. In 12 of his 17 seasons, the defense finished the season ranked in the top 10. “I thought, shoot, the guy could play forever and would play forever,” said Colts Coach Chuck Pagano, who was the Ravens’ defensive coordinator last year. “Great person, great man, great player, just an unbelievable human being — what he’s done for that organization, that city and, for that matter, so many people. He’s obviously a first-ballot Hall of Famer and will be sorely missed.” If the timing of Lewis’s announcement was a surprise, the substance was not. He has hinted that his career was nearing its end and that he wanted to be home to see his son, Ray III, play in the fall at Miami. “God is calling,” Lewis said. “My children have made the ultimate sacrifice for their father for 17 years. I don’t want to see them do that no more. I’ve done what I wanted to do in this business, and now it’s my turn to give them something back.”