Mondesi was hitting seventh in the Royals' posted lineup for Tuesday night's game at Tampa Bay.
"I feel good," Mondesi said. "Feels good just being around these guys again. It was a long process. The only thing I could do is just stay positive and keep doing all my things to get here."
Mondesi was hurt in the Royals' final spring training game on March 29. He appeared in eight rehab games with Triple-A Omaha and Double-A Northwest Arkansas.
"That's why I played a couple more games in Triple-A because I wanted to be sure I was 100 percent," Mondesi said. "Try to be a healthy person, not trying to rush."
Mondesi led the team in runs (22), hits (32), extra-base hits (14), RBIs (20) and on-base percentage (.408) last September. He became the eighth player to record the combination of 14 extra-base hits and 16 stolen bases in a calendar month, and the first since Jose Reyes in April 2007.
Also, Royals manager Mike Matheny said outfielder Hunter Dozier, sidelined by a concussion and rehabbing at Omaha, "seems to be getting his timing right."