In their rise to prominence in recent seasons, the Rays have relied more on bullpen success than almost any team in baseball. But so far in 2021, while facing a litany of injuries, Tampa Bay’s relief corps hasn’t been its usually stout self -- putting a finer microscope on the efforts of the rotation.

Ryan Yarbrough is a key cog in that rotation, but he struggled mightily on Wednesday in a 9-2 loss against the Red Sox at Fenway Park. In the process, Yarbrough extended his winless streak to a franchise-record 19 starts, dating back to Aug. 17, 2019.

• Box score

The “win” stat is a team stat, of course, earned collectively when hitting, pitching and fielding succeed in concert. But wins are tied to pitchers in the box score, rightly or wrongly, and Yarbrough continues to come up on the short end.

“[Yarbrough] looked good early on, they just got to him,” Rays manager Kevin Cash said. “Certainly it wasn’t on the pitching. We just have not been playing good baseball the last couple days.”

As Cash said, Yarbrough was solid early on. He worked 3 1/3 scoreless innings -- at the time, extending his regular-season streak to 18 1/3 innings -- before yielding an RBI single to Xander Bogaerts. In the fifth, everything fell apart for the lanky left-hander.

With Tampa Bay trailing by two, Boston broke out for a five-hit, six-run frame. That could’ve been avoided if not for a two-out, Fenway-sized double issued to J.D. Martinez, in which his fly ball landed high on the face of the Green Monster and registered a .030 expected batting average, per Statcast. Three at-bats later, Willy Adames spiked a throw to first on a routine grounder and two more runs scored.

“Every field has its quirks,” third baseman Joey Wendle said in regard to Martinez’s double. “I mean, we’re going back to the Trop with a white ceiling, so that might affect the game for better or for worse when we get back there. That’s just part of baseball.”

Yarbrough, who allowed the lowest average exit velocity in the Majors last season (82.6 mph, minimum 150 batted ball events), was up to his usual soft-contact-inducing ways again. He allowed an average exit velocity of 84 mph, per Statcast, but the Red Sox made the most of their limited pop: Three of six hard-hit balls versus Yarbrough produced runs.

“I think it was a matter of some pitch execution, trying to throw to certain areas and missing across the plate,” Yarbrough said. “With a team like this that hits the ball really well, you can’t really do that. I feel like that was the biggest thing those last couple of innings.”

The Rays believe in Yarbrough’s ability as a starter, which is why he slots in at No. 2 in the rotation behind ace Tyler Glasnow. But Yarbrough has filled all sorts of roles in his three-plus seasons with the Rays, from starter, to reliever to “bulk” pitcher (i.e. entering after an opener).

Oddly enough, Yarbrough’s career numbers as a reliever (23-5, 3.63 ERA) are notably better than his numbers as a starter (5-12, 4.35 ERA). Starting, Yarbrough insists, is what he wants to do.

“But at the same time, we’re trying to win some ballgames,” he said. “Those things kind of take care of themselves. Just trying to worry about starting right now and let everything take care of itself.”

Boston bashed double-digit hits in all three games of the series, en route to its first sweep of Tampa Bay at Fenway in three years. The Rays’ bats stayed mostly dormant, producing just five hits in the game and 20 in the series.

To start earning wins -- not just for Yarbrough, but for the team -- Tampa Bay has to improve in all facets of the game. Friday’s home opener, in front of a reduced-capacity sellout crowd, would be a great time to do that.

“Maybe good timing that that off-day is coming [Thursday], and then we get to go back home,” Cash said. “Maybe hit a little bit of a reset button.”