BATON ROUGE (AP) — Heisman Trophy finalist Tyrann Mathieu was kicked off LSU’s football team Friday for breaking an athletic department rule, a blow to the Tigers’ national championship hopes three weeks before their season opener.

The junior defensive back — nicknamed Honey Badger for his tenacious style, small stature (5-foot-9, 175 pounds) and blonde streak of hair — rose from obscurity to become one of college football’s biggest stars last season.

He was a sleeper Heisman candidate as the Tigers won the Southeastern Conference championship and reached the BCS title game. But almost as quickly as Mathieu rose to fame and became the face of LSU football, the Honey Badger phenomenon ended in Death Valley.

“We’ll miss the guy,” coach Les Miles said at a news conference. “The football team’s got to go on. We’ll have to fill the void.”

Miles would not specify the reason Mathieu was dismissed. His Tigers are still among the favorites to win the national title this year, even without Mathieu.

Athletic Director Joe Alleva said Mathieu, who was suspended for a game in 2011 after failing a drug test, violated an athletic department rule and had his scholarship revoked.

The Times-Picayune of New Orleans, citing an unidentified person close to the player, reported that Mathieu failed another drug test. Several high-ranking LSU administrators said they either did not know which rule Mathieu had violated or refused to discuss the matter. School policy allows for a player to lose his scholarship even without another positive test if he does not fulfill all the terms of university probation

“Being an athlete is a privilege,” Alleva said. “It’s a privilege and you have to follow the rules to take advantage of that privilege. And unfortunately, he doesn’t have that privilege here anymore.

“He really is a good kid. It’s a shame. But I told him this morning that he has the rest of his life and his life is still ahead of him. He still has a tremendous opportunity to do good things and I encouraged him to do those good things, and I think he will.”

Alleva said the violation did not involve law enforcement and that the university had been trying to help Mathieu work through some unspecified issues.

“He’s had help,” Alleva said. “And we’ve been trying to help him all along in everything. We do everything we can to help these kids.”

Mathieu could stay at LSU and pay tuition, but Alleva said that was unrealistic.

“He’s not going to stay in school,” he said.

The Tigers are No. 1 in the coaches’ preseason poll. The AP college football poll will be released Aug. 18

The Tigers open the season at home Sept. 1 against North Texas. Their only big nonconference test comes the next week when Washington and star quarterback Keith Price visit Tiger Stadium. LSU opens SEC play on the road Sept. 22 at Auburn and renews its rivalry with Alabama on Nov. 3 in Death Valley.

“I called on the leadership of this team to understand that these things happen,” Miles said

The 20-year-old Mathieu won the Bednarik Award as national defensive player of the year last season and was a big-play machine at cornerback and special teams. The All-American scored four touchdowns — two on punt returns and two on fumble returns — intercepted two passes, caused six fumbles and recovered four.

LSU went 13-0 on its way to the BCS title game, and it seemed every time the Tigers needed to a game-changing play, Mathieu delivered.