"Bruce is a real strong kid," pitching coach Jeff Jones said after Rondon's scoreless sixth inning in a 6-5 Tigers loss. "When I talked to the trainers before I got down here, that's what they kept telling me, how strong he was. They didn't feel it was going to be a problem. Hopefully there will be no setbacks. He's worked extremely hard to get where he's at now."
The next few weeks will tell whether Rondon gets ready in time for Opening Day. Whenever he returns, however, he's bringing his fastball with him.
Rondon threw 15 pitches, nine for strikes. He didn't hit 100 mph again, but he hit 99 once more before throwing 98 on his final pitch, another flyout.
Mixed in were mid- and upper-80s sliders and changeups, pitches that the Tigers worked to have him throw before the surgery.
"He threw a couple of good changeups," Jones said. "His slider was just OK. Usually the breaking ball is the last one to come. I was very happy with him."
The only damage off Rondon was a two-out double by Phillies catcher Cameron Rupp, who turned on an 87-mph slider and sent it into left. Rondon's final two pitches from there were fastballs to speedy Ben Revere.
How Rondon feels on Friday will be the next test for the 24-year-old Venezuelan, and will determine how the Tigers progress with him from here. Even with more than three weeks to get Rondon ready for the season, manager Brad Ausmus is cautious enough that he isn't guaranteeing anything for him.
After all, Rondon spent the first half of last Spring Training seemingly in decent shape before feeling discomfort in his elbow in mid-March, the same problem that ended his 2013 season in mid-September. Tests revealed that the source of pain was a torn ulnar collateral ligament, requiring surgery near the end of Spring Training.
"I mean, the same thing we've said about Miggy and Victor applies to Rondon," Ausmus said Wednesday of rehabbing stars Miguel Cabrera and Victor Martinez. "The important thing isn't having them ready for Opening Day. The important thing is having them for the bulk of the season, or as much of the season as you possibly can."
The Tigers struggled all last season to fill Rondon's void, from moving Joba Chamberlain into higher-leverage situations to giving up two well-regarded prospects for Joakim Soria at the July 31 non-waiver Trade Deadline.