"He looked really good," Ausmus said.
Or as teammate Justin Verlander described it, "Awesome."
Rondon, who had March 2014 Tommy John surgery, threw all of his pitches on Monday, including the slider that tends to put more stress on the arm, but it's the fastball that caught the attention. He didn't always command it, evidenced by a near-miss on teammate Andrew Romine in the box. But he was able to cut loose with it.
Rondon, who missed all of last season following the surgery, has been on the disabled list since Opening Day with biceps tendinitis. He has progressed before, only to be halted by lingering soreness.
"The thing with him, it's been the day after," Ausmus said of Rondon, who complained of soreness in the past a couple of times after throwing sessions. "So we are keeping our fingers crossed that it'll be the same as his recent track record where he's felt pretty good coming in the next day. We will know more tomorrow. But as far as his simulated game or live BP, he looked strong."
Assuming Rondon feels fine Tuesday, Ausmus said he'll talk with pitching coach Jeff Jones to determine whether Rondon throws to hitters again in Detroit this week or goes on a Minor League rehab assignment.
Before Rondon went to work, Verlander threw a 45-pitch bullpen session that included all of his pitches, notably the curveball that caused him issues during his previous ramp-up last month. He felt what he called "normal fatigue" but otherwise felt fine.
"By far the most intense bullpen I've thrown yet," Verlander said. "It was all good."
Ausmus said Verlander will probably throw one more bullpen session, this time sitting down and getting back up to simulate time between innings, before deciding on a rehab assignment.
"He's moving forward," Ausmus said, "but we were kind of at this point earlier in the season, too, and we had a setback. So that's more reason to be cautious. We don't want to revisit that."
Other injury notes
• Shane Greene threw a light bullpen session Monday and said he's on track to make his scheduled start Wednesday night against Milwaukee. Greene, who left Friday's start at St. Louis with mild ulnar neuritis, said he has had no tingling in his arm since that night. "I'm relieved," he said.
• Catcher Alex Avila has started his rehab work as he tries to strengthen his left knee. Avila, who went on the 15-day DL last week after being diagnosed with a loose body in the knee, said he's working on strengthening the muscles. He doesn't have a timetable yet on a return, he said, but hopes to know more later in the week.