"It felt a little unpleasant at first, but I've kept on doing it," Shin said Thursday before the Heroes' game against the Kia Tigers at Gocheok Sky Dome in Seoul. "I think it does help with my blister. Even Esmil Rogers and Jake Brigham have recommended it," he added, referring to his foreign teammates.

Shin went 15-7 with a 3.90 ERA in 2016 to earn the top rookie honors. But he slumped to a 6-7 season in 2017, while his ERA also went up to 4.54. This year, Shin has been even worse, posting a 7.56 ERA and a 2-4 record in nine starts.

Shin had to cut his most recent start short after five innings on Wednesday because of a blister on his right middle finger.

Shin held the Tigers to a run on five hits through five innings. He'd only thrown 71 pitches and could have stayed in the game for a couple more innings if not for the blister. He has yet to pitch more than six innings this year.

And Shin didn't even get a win in the end. The Heroes' bullpen blew a 7-1 lead and let the Tigers tie the score at 7-7 in the seventh inning, before rallying to win 8-7.

Manager Jang Jung-suk said after the game that though Shin's blister was small, he took the pitcher out of the game for precautionary reasons.

And no one is more frustrated than Shin himself.

"As long as my finger holds up, I can go deep into games," he said. "I threw more than 100 pitches a game in spring training."

Shin blamed his blister issue on sweaty hands. When he picks up the rosin bag with a sweaty hand during games, the hand will go dry quickly and start cracking.

He recently purchased an electronic device to treat excessive sweating and is considering undergoing operation to remove sweat glands after this season.

"On Wednesday, it was a bit humid inside the dome because it was raining, and that's why I had that small blister," Shin said. "I've been trying to take care of it but it's been so tough. Because of the rules, I have to watch what substances I put on my hand, too." (Yonhap)