The 25-year-old right-hander has not pitched since May 3. He went on the disabled list because of groin discomfort, but five days later he underwent surgery for suspected, and later confirmed, testicular cancer.
Taillon resumed baseball activities a few days later and had three productive rehab starts in the minors.
"Physically, mentally, I'm 100 percent," Taillon told reporters on Saturday. "I'm as sharp as I've been all year. If anything, I had some time while I was away to work on things I wanted to get done and sharpen up. I'm probably in a better spot now than I was before."
Taillon has a 2-1 record and 3.31 ERA in six starts this season.
To make room on the roster for Taillon, the Pirates optioned right-hander Tyler Glasnow to Triple-A Indianapolis. Glasnow has a 2-6 record with a 7.45 ERA this season.