Anthony Bonsante had been contemplating retirement for some time. At age 38, the Shakopee boxer knew he was pushing the limits of his time in the ring, but he found it difficult to fully embrace the next phase of his life when he still felt so vital and strong.

As he prepared for last Saturday's fight against Andy Kolle -- 12 years his junior -- Bonsante reveled in the routine of cutting weight and refining muscle. And when he struck the canvas in the third round, victim of Kolle's pile-driver of a left hand, he knew instantly that it was over. Bonsante announced he is ending his 13-year pro career, stepping out of Minnesota's crowded middleweight division after 2 1/2 years as its champion and a longer run as one of the state's most popular boxers.

He felt certain of his decision, but that didn't make it any easier to leave. When the staff at Hinckley's Grand Casino began tearing down the ring, Bonsante asked them to stop, then summoned his family to join him for a final photo inside the ropes.

"It was tough, really tough," Bonsante said, his voice still halting with emotion the day after the fight. "I didn't want it to end, but it did, and I know it's going to take a while to sink in.

"I knew if I couldn't beat Andy, there was no way I could get back to the top. And if I can't get back to the top, there's no point in staying. I've had a great career, with a lot of great people looking out for me, and it's been a lot of fun."

Bonsante steps away with a 32-11-3 record, two title belts, memorable bouts at Madison Square Garden and Caesar's Palace and a measure of celebrity from his stint on the reality-TV show "The Contender." More importantly, he proved that every fighter does not wind up broke and broken.

Pro boxing has declined in the American consciousness largely because of its inability -- or unwillingness -- to rid itself of the crooked promoters and self-serving managers who exploit young talent. Bonsante avoided that trap by surrounding himself with people of integrity, including longtime trainer Bill Kaehn and cornerwoman Lisa Bauch. His broad and well-grounded view of life, shaped in part by college and fatherhood, led him to maintain control of his career.

Bonsante understood from the beginning that boxing is a gift with an expiration date. He kept his job as a supervisor at Shakopee's Kmart warehouse, where he has worked for 16 years, and lived a modest lifestyle with a plan that reached well beyond the ring. Because he never viewed himself solely through the athlete's narrow prism, he is able to retire from the game with his body and mind intact.

Though Bonsante could still pack a punch, he recognized in recent months that his reflexes and speed had begun to wane, leaving him more vulnerable. Kaehn, 85, supported his decision to move on, as did Bonsante's family.

"This is the right call," Kaehn said. "Tony is the kind of kid who wouldn't want to go out with a loss. But he is going out as a champ, because of the way he handled his career."

Kolle, 26, won the state middleweight title with Saturday's TKO. Now 18-2, his only losses came to 2004 Olympic gold medalist Andre Ward -- undefeated in 18 pro fights -- and World Boxing Organization welterweight champ Paul Williams.

He tops a wealth of popular, promising middleweights now filling cards in Minnesota. The gritty Matt Vanda, whose 2007 loss to Bonsante matched the state's biggest names in a bout that drew nearly 9,000 people to Target Center, is enjoying a resurgence; now 30, he went the distance against undefeated champs John Duddy and Julio Cesar Chavez Jr. in his past two fights. Others include 11-0 Caleb Truax and Golden Gloves champ Cerresso Fort.

Bonsante intends to stay involved with the sport. Kaehn already has spoken with him about becoming a trainer, and he also hopes to be part of the Minnesota Combative Sports Commission. He also plans to run for Shakopee's school board this fall.

Kaehn said he was never more impressed with Bonsante than he was Saturday night, when the beaten fighter lauded his opponent and thanked Minnesotans for supporting his career. As he walked out of the spotlight for the final time, his song -- "I Got It Honest" -- played over the sound system.

"I love this sport," Bonsante said. "I've done it for 26 years. But a true champion knows when to step away."

Rachel Blount is at rblount@startribune.com