But after the young hurler had some time to release his frustrations, he returned to Great American Ball Park on Sunday afternoon and at least admitted the control issues he's had in his past two starts could be attributed to the blister.
"It's just my location and my velocity is down a little bit," Jurrjens said. "I don't know. Maybe I'm just scared to put pressure on the thumb."
At the same time, Jurrjens wanted to make sure he was wasn't using the blister as an excuse to explain why he hasn't been able to pitch at least five innings in either of his past two starts.
"If I didn't think I was going to be able to do the job, I'd have said something," Jurrjens said. "But I took the ball, so there are no more excuses."
During his first 10 starts of the season, Jurrjens went 5-3 with a 2.64 ERA, limiting opponents to a .219 batting average and pitching into the sixth inning eight times. The blister, which is located on the left edge of the thumb, developed during the seventh inning of his May 21 start, during which he allowed just two runs -- one earned -- in seven innings against the Mets.
In the two starts that have followed, he's totaled nine innings, posting a 9.00 ERA and watching opponents produce a .405 batting average with a .490 on-base percentage.
Jurrjens says the blister has the greatest effect on his two-seam fastball, a pitch he estimates he uses 50 percent of the time during any game.
Over the past week, Jurrjens has been applying Stan's Rodeo Cream on the blister and realizing some positive results. Jo-Jo Reyes used the same ointment when he was battling a blister two weeks ago.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.