OAKLAND -- In Bob Melvin's time managing in the big leagues, he's never had a closer with stuff as dominant as Blake Treinen.
As the A's closer celebrates his 30th birthday on Saturday, he has established himself as one of the elite back-end pitchers in the game. Treinen is in the midst of a career year. In 33 appearances, his ERA is a miniscule 0.89, which leads American League relievers and ranks second in the Majors.
Treinen has converted his last 18 save opportunities and hasn't blown a save since April. He nailed down his 21st save of the season on Friday against the Indians.
"If anybody has a profile of stuff to be a closer, it's him," Melvin said.
Treinen spent his first three seasons with the Nationals, where he pitched well but didn't close games. He was acquired by the A's in a trade in July of last season, and Melvin trusted him right away. Treinen saved 13 games for Oakland to end the 2017 campaign.
"He's come a long way since he's been here and has nailed down the closer role since the minute he got here," Melvin said.
Treinen's pitches -- a fastball that reaches 100 mph, along with a power sinker and slider -- are vicious.

"Not too many guys have that kind of stuff," Melvin said. "There's a mentality to closing that can be difficult for anybody, but it does not seem like it's the case for him."
Treinen has also developed the ability to finish games even when he isn't 100 percent. On Friday, he allowed two runners to reach, putting the tying run on base with a two-run lead, but he induced a game-ending flyout by Jason Kipnis.
"Still got to be in the zone," Treinen said. "You're not always going to have your best stuff or location."
Finding that zone comes with gaining confidence, which is all part of the evolution of a closer, Melvin said, and Treinen anchors an A's bullpen that is oozing with confidence. The A's are 31-0 when leading after the seventh inning this season, the only team to be undefeated when leading after seven frames. The bullpen has a 2.70 ERA and has held opponents to a .194 batting average since May 1 and ranks first in the Majors in winning percentage on the year (19-7, .731).
"[We have] seven to eight guys down there who can take the ball any time that have experience on the back end," Treinen said. "It's a blessing to have on this team."
The A's have been bolstered by the emergence of rookie Lou Trivino as the setup man, veterans such as Yusmeiro Petit and Santiago Casilla and improvements from Emilio Pagan and Chris Hatcher. But it's Treinen with the most important job of them all.
"It was easy to put him in the closing role as long as he was comfortable with it right away," Melvin said. "He was comfortable doing it. He's carried that torch ever since."