CLEVELAND -- The A’s bullpen is about to get a little more electric.

In advance of Tuesday's three-game series opener against the Indians, the A’s recalled top pitching prospect A.J. Puk from Triple-A Las Vegas. To make room on the club’s active roster, right-hander J.B. Wendelken was designated for assignment.

“I have been hearing that he’s been pitching really well,” A’s manager Bob Melvin said. “You see the numbers. He’s also a bit stretched out, which is good for us. It gives us a third lefty. Whenever you have a guy that throws 98 mph and has a good slider, it’s always a good target date for him to come up.”

Puk, ranked Oakland’s No. 2 prospect by MLB Pipeline, returns after he made one appearance for the club on April 5 -- an impressive relief appearance of 3 1/3 scoreless innings against the Dodgers -- before landing on the injured list with a left biceps strain. Going through some early struggles at Triple-A upon his recovery from the injury, Puk has been performing in a fashion reminiscent of his 2019 campaign, which saw him emerge as a multi-innings bullpen weapon for the A's down the stretch.

Overcoming a period in which his velocity decreased in Spring Training and carried into the early part of the Minor League season as he worked his way back from left shoulder surgery on Sept. 11, 2020, Puk has regained that velocity as of late. His fastball is once again sitting around 98-99 mph while pitching out of the bullpen for Las Vegas. Dating back to July 6, the 26-year-old has allowed just four runs over his last 10 appearances with 18 strikeouts and two walks across 17 2/3 innings.

Puk can trace back to the exact moment when things began to turn around for him at Triple-A. It started on June 5 during a game against the Albuquerque Isotopes. At the time, Puk said he “wasn’t feeling good at all” as his fastball velocity hovered around 92-93 mph during his first week of outings back from the biceps issue. Having tinkered with a lower arm slot while playing catch before that June 5 game, he decided to use it for his final four pitches of his appearance that day. Since then, Puk has maintained that new arm slot, which he said is about a four to six inch drop from his original angle. In turn, his velocity gradually began to increase over that time to what it is now.

“All the nerve symptoms I was getting went away, and I’m feeling good,” Puk said. “[The velocity came] back naturally after I dropped the arm angle. It just kept getting stronger in that slot. I didn’t know when it was gonna come back, but it came back.”

There might come a point when the A’s attempt to convert Puk back into a starting role. But for this season, with Oakland in the middle of another playoff race as it entered Tuesday tied for the top American League Wild Card spot and just two games back of Houston for first place in the AL West, the 6-foot-7, 248-pounder presents an opportunity to bolster the bullpen as another high-leverage relief option in the late innings. Though to start out, Melvin said the left-hander will likely be utilized for length in lower-leverage spots, with a chance to elevate his positioning if he continues to pitch well.

“We have two lefties before him in more prominent roles late in games,” Melvin said. “Whether he gives us length or pitches well and pitches himself into a different spot, it’s probably more in behind games or when we need a couple of innings, at least to start.

“Sometimes, you just have to see how it works out.”

Oakland has already seen what Puk’s power arm and ability to pitch multiple innings could provide in shorter bursts when he received his first callup to the Majors in 2019. Puk, selected sixth overall by the club in the 2016 MLB Draft, helped the A’s to a berth in the AL Wild Card Game that year, posting a 3.18 ERA in 10 relief outings while showing off a blazing fastball that touched triple digits.

“Super excited to be up here and help out this team,” Puk said. “It seems like since I’ve been here, they always put together a good run. Hopefully, we can finish it out this year and I can earn a spot some place in the bullpen.”