Though Beltran remained in the game for another three innings, the right fielder felt increasing tightness as the afternoon progressed. Manager Mike Matheny said he noticed Beltran having less-than-normal zip throwing two balls back to the infield in the top of the fifth. Beltran hit in the bottom half of the frame but did not return to the field in the sixth.
The issue isn't expected to keep Beltran out of the lineup for long. His status, like that of David Freese and Lance Berkman, is considered day to day.
"Where it hit him, I think it's more muscular than anything involving the bone," Matheny said. "We'll keep an eye and add him to that list that we'll keep watching."
Beltran made the most of his playing time on Sunday, reaching base three times and scoring three runs. He also stole a base, his second of the year.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.