Aaron Sanchez has had a frustrating 2017 season.

The Barstow High School grad was pulled from his Wednesday start against the Boston Red Sox with a blister on the middle finger of his throwing hand.

Sanchez allowed five runs on six hits and five walks through just four innings, ending his four-game win streak against Boston.

“It just started forming midway through the game and I kept going and it got worse,” Sanchez told reporters on Wednesday. “The right thing to do is to kind of catch it before things (get) worse."

This blister struggle comes a season after Sanchez led the American League with a 3.00 ERA and put together a 15-2 record.

In just eight starts for the Toronto Blue Jays this season, Sanchez has a 4.50 ERA and a 1-3 record. He has landed on the DL with a blister three times this season. 

"It's one of those things I can’t control. It’s definitely frustrating," Sanchez said. "You take a step forward, you think you're past it and you're right back to step one."

Sanchez joins other formidable names that have been hit with this blister plague. Teammate Marcus Stroman, the Dodgers’ Rich Hill and the Mets’ Noah Syndergaard have all experienced blister issues this season.

Stroman was also pulled early from his July 3 start against the Yankees to prevent his blister from turning into a serious issue and he was not placed on the DL.