(AP) -- Hall of Famer Tony Gwynn has died of cancer at 54.

Gwynn's sweet left-handed swing made him one of San Diego's best-loved athletes. He was nicknamed "Mr. Padre" during his 20-year major league career.

"For more than 30 years, Tony Gwynn was a source of universal goodwill in the national pastime, and he will be deeply missed by the many people he touched," Commissioner Bud Selig said.

Gwynn had been on a medical leave from his job as baseball coach at San Diego State, his alma mater, since late March. Agent John Boggs said Gwynn died Monday at a hospital in suburban Poway.

Gwynn had two operations for cancer in his right cheek between August 2010 and February 2012. The second surgery was complicated, with surgeons removing a facial nerve because it was intertwined with a tumor inside his right cheek. They grafted a nerve from Gwynn's neck to help him eventually regain facial movement.

Gwynn had said that he believed the cancer was from chewing tobacco.

In a rarity in pro sports, Gwynn spent his entire 20-year career with the Padres, choosing to stay rather than leaving for bigger paychecks elsewhere. His terrific hand-eye coordination made him one of the game's greatest contact hitters. He had 3,141 hits, a career .338 batting average and won eight NL batting titles. He excelled at hitting singles the other way, through the "5.5 hole" between third base and shortstop.

Gwynn played in the Padres' only two World Series and was a 15-time All-Star.

He homered off the facade at Yankee Stadium off San Diego native David Wells in Game 1 of the 1998 World Series and scored the winning run in the 1994 All-Star Game. He was hitting .394 when a players strike ended the 1994 season, denying him a shot at becoming the first player to hit .400 since San Diego native Ted Williams hit .406 in 1941.

Gwynn befriended Williams and the two loved to talk about hitting. Gwynn steadied Williams when he threw out the ceremonial first pitch before the 1999 All-Star Game at Boston's Fenway Park.

Gwynn retired after the 2001 season. He and Cal Ripken Jr. -- who spent his entire career with the Baltimore Orioles -- were inducted into the Hall of Fame in the class of 2007.

Gwynn was a two-sport star at San Diego State in the late 1970s-early 1980s, playing point guard for the basketball team -- he still holds the game, season and career record for assists -- and outfielder for the baseball team.

Gwynn always wanted to play in the NBA, until realizing during his final year at San Diego State that baseball would be the ticket to the pros.

"I had no idea that all the things in my career were going to happen," he said shortly before being inducted into the Hall of Fame along with Cal Ripken Jr. in 2007. "I sure didn't see it. I just know the good Lord blessed me with ability, blessed me with good eyesight and a good pair of hands, and then I worked at the rest."

He was a third-round draft pick of the Padres in 1981.

After spending parts of just two seasons in the minor leagues, he made his big league debut on July 19, 1982. Gwynn had two hits that night, including a double, against the Philadelphia Phillies. After doubling, Pete Rose, who had been trailing the play, said to Gwynn: "Hey, kid, what are you trying to do, catch me in one night?"