Some of the sports stories The Associated Press is covering Tuesday. A full Sports Digest will be sent by about 3 p.m. All times EST:

- MOSCOW - Three of Maria Sharapova's major sponsors - Nike, Tag Heuer, Porsche - cut ties with her after she says she failed a doping test at the Australian Open.

- MOSCOW - Meldonium, the drug at the center of Maria Sharapova's case, is usually prescribed for medical use for four to six weeks. It was regularly given to Soviet troops in the 1980s to boost stamina.

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- With the NFL's salary cap up about to more than $155 million, the free-agent spending spree begins Wednesday. Some teams that opened their vaults recently have prospered - like the Broncos.

- DETROIT - Calvin Johnson, one of the most spectacular receivers in NFL history, retires from the Detroit Lions at age 30.

- KANSAS CITY, Mo. - The Big 12, led by No. 1 Kansas and widely considered the toughest league in college basketball, is set for what is expected to be one of the most interesting conference tournaments.

- INDIANAPOLIS - Two months after being discounted, overlooked and forgotten by many, No. 10 Indiana heads to the Big Ten Tournament as the No. 1 seed.

- Men's conference finals (NCAA spots): Horizon - Green Bay vs. Wright St. (7 p.m.); Fairleigh Dickinson vs. Wagner (7 p.m.); North Dakota St. vs. South Dakota St. (9 p.m.); Saint Mary's vs. Gonzaga (9 p.m.)

- Women's conference finals (NCAA spots): Summit - South Dakota vs. South Dakota St. (2 p.m.); West Coast BYU vs. San Francisco (4 p.m.); Big East - Creighton vs. St. John's (8 p.m.)

- NEW YORK - Serena Williams returns to the court for the first time since losing the Australian Open final when she faces Caroline Wozniacki in an exhibition. Also, Stan Wawrinka plays Gael Monfils.

- BALTIMORE - Michael Phelps is training hard for the 2016 Olympics, confident his hard work will result in success at Rio.

- JUPITER, Fla. - Marlins reliever Carter Capps, expected to contend for the closer's job, will miss the entire season. He has a torn elbow ligament and will have Tommy John surgery.

- FRANKFURT, Germany - Franz Beckenbauer won the World Cup as a player and a coach, and then brought the showcase tournament to his German homeland. It's in that role that his image could be stained.