And manager Jim Leyland says Valverde will be Detroit's closer.
Valverde was the Tigers' closer the past three years, but the team was prepared to let him leave as a free agent after he faltered during the 2012 postseason. However, he never signed elsewhere, and Detroit brought him back on a minor league deal.
He pitched three scoreless innings at Class-A Lakeland, and now he's being called back up to the majors.
"I'm ready to pitch," Valverde told ESPN The Magazine while at the Detroit airport Tuesday. "I feel good. The last couple of days I threw in Lakeland, I threw 96 [mph], 97, a couple times 98."
Detroit optioned right-hander Brayan Villarreal to Triple-A Toledo, and the Tigers expect to make another move to clear space for Valverde on the 40-man roster.
ESPN The Magazine's Craig Custance and The Associated Press contributed to this report.