Rondon was called up after the Tigers placed right-handed reliever Octavio Dotel on the disabled list retroactive to April 20.
Rondon was auditioned this spring by the Tigers for the closer's role, but struggled with control and the pressure of pitching back-to-back days.
In turn, the Tigers sent him back to Triple-A Toledo to see how he could fare as a closer on that level while the big club decided to start the season by going with a closer-by-committee approach.
Rondon has excelled in his opportunity with the Mud Hens.
In seven appearances, Rondon has finished six games, saving three. In 7.2 innings, he has struck out nine while walking two. He has not given up a run and scattered five hits.
With the closer's situation still unsettled, and with former closer Jose Valverde undergoing extended spring training with a minor league contract, it remains to be seen whether Rondon will be given a couple of weeks to join that closing committee or if he will take Dotel's role of a seventh inning/setup up pitcher.
The Tigers have struggled out of the gate, going 9-9 in their first 18 games, and have only three saves so far. Joaquin Benoit and Phil Coke have finished 10 of the 18 games the bullpen has entered.
By and large, the Tigers have had good pitching. Their 3.70 ERA is fifth in the American League.
Still, the collective bullpen has a record of 1-4 with an ERA of 4.53.
With nagging injuries to Dotel and a slow start to Brayan Villarreal, they may find both Rondon and Valverde helpful, even if they do not close.