Glasnow allowed two runs on three hits and exited with Tampa Bay leading 3-2 in a matchup of teams that entered with the two best records in the majors. The 6-foot-8 right-hander walked one and struck out six, throwing 40 of 53 pitches for strikes.
Speaking after the Rays' 5-2 win, Glasnow said he sensed something wasn't right, but not terribly painful, in the elbow as he tossed his final pitches in the fourth. He told the coaching staff and was replaced by Ryan Thompson.
"The last couple of pitches I felt just a little tug,'' Glasnow said. "I didn't want to go out and chance it. The velo was still there; it just felt not right.''
Glasnow said he planned to get an MRI on Tuesday.
The 27-year-old pitcher is 5-2 with a 2.66 ERA this season and is 10-2 over his past 21 starts dating to Aug. 12, 2020.
Information from The Associated Press was used in this report.