When Amir Garrett played basketball for St. John’s University, he was the classic prototype: loved by his teammates and loathed by his opponents.

“What he brought was fire, competitiveness, spirit, toughness, tenacity,” said Steve Lavin, his coach there. “He did it all-out every time he stepped on the court. He was like a Danny Ainge or an M. L. Carr — he’d try to get under opponents’ skin. He played with a chip, a hard edge.”

Garrett played two seasons for the Red Storm, but he was already a professional baseball player when he arrived on campus. He reached the majors this month as a starting pitcher for the Cincinnati Reds, and has a 1.83 earned run average in three quality starts. Garrett, who will turn 25 next month, works with style, beginning each inning by scratching a large letter A on the mound with his spikes.

For the rebuilding Reds, who have made a respectable start to the season, he has been a wise investment. They drafted Garrett in the 22nd round out of a high school near Las Vegas in 2011, gave him a $1 million bonus and let him follow his other passion in the off-seasons. Garrett chose St. John’s.