ARLINGTON -- The Rangers’ bullpen has been the subject of a ton of criticism over the past year. The struggles were obvious throughout the 2023 season and early this year, things have been a bit of a roller coaster.

Now, you don’t hear much about the bullpen. That’s maybe for the best.

In the Rangers’ 4-3 loss to the Mariners on Thursday afternoon at Globe Life Field, starter Andrew Heaney gave Texas six innings, his longest outing of the year, but he was tagged with the loss due to a pair of two-run homers.

Though Texas dropped the series -- its second straight -- the bullpen shined over the three games. On Thursday, it was thanks to a combined three perfect innings from rookie Cole Winn and the recently activated Josh Sborz, neither of whom has allowed a run yet this season.

Over the last four games, the bullpen has held opponents to just one unearned run over 15 innings on five hits, three walks and 16 strikeouts.

The offseason additions of David Robertson (1.26 ERA) and Kirby Yates (0.00 ERA) have tremendously paid off, and with Sborz and Jonathan Hernández both returning from the injured list this week, roles are becoming more defined in the bullpen as things get better and better.

“We're all excited about where we're at with the bullpen,” Rangers manager Bruce Bochy said. “It's always good to get your guys back, so it's all coming together.”

For all the veteran success in the bullpen, maybe the biggest shock of the young season has been the emergence of Winn, who Bochy called a “bright spot.”

Once the Rangers' top pitching prospect after the club selected him at 15th overall in the 2018 MLB Draft, Winn began transitioning to the bullpen midway through the 2023 season after consistent struggles as a starter with Triple-A Round Rock in the hitter-friendly Pacific Coast League. The right-hander ended '23 as Texas’ No. 14 prospect.

Winn was the Rangers' 2021 Nolan Ryan Minor League Pitcher of the Year. He then posted a 6.51 ERA in 28 starts in '22 and a 7.22 ERA in 29 games (13 starts) in '23, and it seemed like he wouldn’t be a big league option any time soon.

But before anybody could blink, Winn was called up after a rash of injuries to the Rangers’ bullpen and has looked the part of a big leaguer.

“I’m feeling good,” Winn said. “I feel really good actually. It's been a wild ride, for sure. But the only thing I'm focused on out there is executing pitches, and it's happening more often than not right now. Because the only thing I can control is executing the pitch as soon as it leaves my hand. That's what I'm trying to do.”

Following his two scoreless innings against the Mariners on Thursday, Winn hasn’t allowed a run over the first four appearances (six innings) of his career, holding opposing batters to 0-for-18 with seven strikeouts and one walk. According to Stathead, he is the second pitcher in franchise history to open his career with four straight hitless appearances, joining Wilmer Font from Sept. 18, 2012 to July 12, 2013.

“He’s just been playing really good, hasn't he?” Bochy said. “He’s throwing strikes, he’s going after them. He just looks comfortable out there on the mound. He looks like a Major League pitcher. He is getting better and better. It’s been fun to watch what he's done up here. Now you look at the equipment, he’s pumping 97, and a curveball that he’s landing for strikes and a slider with the splitter, that works up here.”

Bochy isn’t shy about saying that bullpens are fluid. They all go through their ups and downs throughout a season.

Right now is no doubt a high point for the bullpen.

“They’ve been really good across the board,” Bochy said. “Coming in and doing a job and getting big outs when we need it and picking each other up. They're doing all they can to give us a chance to win. So I'm really, really pleased with what's going on down there. These guys, they're ready, and they're coming in and throwing the ball very well right now.”