Glasnow threw 21 pitches to a pair of minor leaguers before the Rays played the Los Angeles Angels. Glasnow had Tommy John surgery on Aug. 4, 2021. The 6-foot-8 right-hander made his last appearance on June 14, 2021, at the Chicago White Sox.
"I think it's like easy to be very optimistic," Glasnow said. "I felt really good, my velo was good, execution was good, but again, if I'm not comfortable and I don't feel like 100 percent and ready to go, then I'm not. I'm not going to push it."
The regular season ends on Oct. 5.
"It's going to be the hardest thing for me to come to the decision," Glasnow added. "I really do want to come back. I want to help the team, especially the position we're in, but I'm not going to jeopardize the rest of my career."
Glasnow, the 2021 Opening Day starter, went 5-2 with a 2.66 ERA in 14 starts last year. He will have one or two more BP outings before the team will decide whether it is time for a minor league rehab assignment.
"He looked certainly healthy," Rays manager Kevin Cash said. "I, myself, as much as anybody, probably have to temper the expectations and the excitement around it but I'm glad he's throwing BPs."
Tampa Bay started Tuesday holding the top American League wild-card spot.
Rays shortstop Wander Franco hit in an indoor cage and took grounders. Franco was removed from his rehab assignment with Triple-A Durham on Sunday due to ongoing hand soreness.
Franco, 21, went on the injured list July 10 with a right hamate bone injury that required surgery. He played part of just one game a week ago with Durham.
Franco on Aug. 14 took on-field batting practice on Sunday for the first time since surgery. After the session, he said he felt great except when taking right-handed swings.
Third last year in the AL Rookie of the Year voting, Franco signed a $182 million, 11-year contract in November that includes a club option for 2033. The deal could be worth up to $223 million with incentives if the club option is exercised.
As part of a series of roster moves, RHP Kevin Herget was designated for assignment. Herget spent a decade in the minors before being selected from Triple-A Durham on Friday but didn't get a chance to make his major league debut.
RHP JT Chargois (left oblique tightness) was reinstated from the 60-day IL. LHP Brendan McKay (thoracic outlet syndrome decompression surgery) was reinstated from the 60-day IL and optioned to Triple-A Durham. RHP Tommy Romero was designated for assignment.