St. Louis Cardinals batting coach Mark McGwire holds a January session with outfielder Colby Rasmus in the batting cage at Busch Stadium in St. Louis. McGwire was due to arrive in Jupiter, Fla., late Tuesday for spring training.

JUPITER, Fla. — Mark McGwire's No. 25 jersey is ready for duty again, hanging outside his locker stall in the St. Louis Cardinals' spring training clubhouse.

The most controversial batting instructor in the major leagues was due to arrive in Jupiter late Tuesday and could be on the field as early as today, the date for pitchers and catchers to report for St. Louis.

Several of his pupils are already here, including second baseman Skip Schumaker, who is among a handful of Cardinals familiar with McGwire's passion for hitting after offseason workouts in California. He's perhaps McGwire's biggest booster on the team, having worked with the slugger he grew up idolizing since 2005.

The leadoff hitter had one complaint: No longer will he have McGwire's undivided attention.

"I'm excited about it," Schumaker said. "I'm not excited I have to share him. He's helped me a whole lot the last couple of years and I'm excited to have him for a full season."

Last month, McGwire ended more than a decade of denials and evasion by admitting that he used steroids and human growth hormone as he became a home run king. Schumaker said teammates will quickly learn that McGwire, though tarred and feathered by many as a poster boy for performance-enhancing drugs and thus far locked out of the Hall of Fame despite his 583 homers, has plenty to offer.

"He preaches consistency and not to have a roller coaster type of year, and to know your swing," Schumaker said. "He's convinced me I know my swing and he's always been super positive."

As early arrivals to camp dodged boxes during the unpacking process from the move south, no one seemed too concerned that a media circus was coming to Roger Dean Stadium, the Cardinals' spring home. Cardinals spokesman Brian Bartow did not expect a crush of national media for the official camp opening, even if McGwire appears to be the biggest story at the outset.

"I'm sure there'll be a lot of stuff going on early, but hopefully that'll all move aside," pitcher Kyle Lohse said. "I've heard a lot of good things about him and hopefully everybody will get their work done in peace."

Big Mac's return to baseball comes just over a month after admitting to steroids use during his dramatic power surge in the 1990s, including his then-record 70-homer season in '98. Whether his confession went far enough is an open question.