Cardinals manager Mike Matheny told Jenifer Langosch of MLB.com that the tightness started to surface Saturday night against the Pittsburgh Pirates. Matheny pulled Beltran in the seventh inning on Saturday night, but said the outfielder was available to pinch-hit Sunday if needed.
Beltran has had a strong offensive season for St. Louis, batting .310/.343/.522 over 500 plate appearances.
St. Louis will start Allen Craig in right field Monday, with Matt Adams replacing Craig at first base. Craig and Adams have both been productive hitters this season, giving the Cardinals some flexibility if Beltran needs to miss more timee.
The Cardinals enter Monday with a 79-57 record, tied with the Pirates for the NL Central lead. The Cincinnati Reds sit 3 1/2 games behind the two leaders, which should make for an exciting final month of the season.