The pitcher joined the Cardinals for workouts on Saturday after spending 16 days in quarantine.
He told reporters that he was asymptomatic and was happy to put the experience behind him.
"It's tough," Reyes said, according to the St. Louis Post-Dispatch. "It's an unfortunate situation, but I also have to be thankful. This virus has affected many lives, and thankfully I wasn't hit with any symptoms [and] nobody who was close to me got infected. It's a huge positive that this is behind me."
Reyes went 0-1 with a 15.00 ERA in three relief appearances with the Cardinals last season.
Once one of the organization's top prospects before a spate of injuries, Reyes remains focused on being a starting pitcher.
"That's my end goal, forever," Reyes said. "I'll never stop working toward that."