Yankees manager Aaron Boone told reporters that Stanton was injured toward the end of defensive drills Tuesday at the George M. Steinbrenner Field complex in Tampa, Fla. Boone said the slugger will be "up against it a little bit" when asked whether he will be ready for the March 26 opener against the Baltimore Orioles.
"It's disappointing because you want to get guys going and built up," Boone said Wednesday. "But it's just a little bump in the road and we're equipped to handle it."
Stanton underwent an MRI exam, which revealed the Grade 1 calf strain. The results were announced less than 24 hours after the Yankees said starting pitcher Luis Severino will miss all of the 2020 campaign due to Tommy John surgery on his throwing elbow.
Stanton appeared in only 18 games last season because of multiple injuries. He recorded a .288 batting average with three home runs and 13 RBIs in 72 plate appearances last year.
In his first season with the Yankees in 2018, Stanton had a .266 average and belted 38 home runs. Before joining the Yankees, he tallied career highs in homers (59), RBIs (132) and slugging percentage (.631) during his final season with the Miami Marlins in 2017.
Stanton signed a 13-year, $325 million contract with the Marlins after the 2014 season. He will earn a base salary of $26 million with the Yankees in 2020.