In 24 appearances with the club, Nesbitt compiled a 5.40 ERA. After allowing opponents to hit just .207 against him through May 18, the righty began to struggle with his command. In eight games since, opponents batted .400 off Nesbitt, who also let eight of 10 inherited runners score during that span.
The tipping point seemed to be Oakland outfielder Ben Zobrist's grand slam against Nesbitt on June 2. In his next outing, Nesbitt hit two batters, and he yielded three runs off a hit and two walks on Wednesday.
"Last couple outings, he had a little trouble throwing strikes, which is uncharacteristic of him," Tigers manager Brad Ausmus said.
Nesbitt has never thrown at the Triple-A level, and Ausmus admitted the righty was a "long shot" to make the team out of Spring Training. But the 24-year-old pitched his way into a roster spot, becoming a near-unanimous selection by the coaches, Ausmus said.
"The truth is, we think the world of Nesbitt," he said. " ... He pitched so well, and we liked his makeup, his work ethic."
Earlier this month, Nesbitt admitted to overthinking while on the mound, a problem that compounded itself into deteriorating command.
"I don't think it'll hurt him in any way to go down there for a little bit, but I would not be shocked if he's back here soon," Ausmus said. "I just think he's too quality of a pitcher and too quality of a person to not be back here."
The Tigers also optioned starter Shane Greene on Friday afternoon. Reliever Bruce Rondon (Tommy John surgery) will make another rehab appearance for the Mud Hens on Sunday, after which a decision will be made about his return to the Tigers.
Alejandro Zúñiga is an associate reporter for MLB.com. Follow him on Twitter @ByAZuniga.