SEATTLE — Two years in a row the Red Sox went into the season with a suspect bullpen that looked like it might be in need of some serious upgrades before the trade deadline.

And two years in a row this group has done a lot to quiet those concerns.

During 2017, the Red Sox traded for Addison Reed, a key piece who fortified the ’pen down the stretch, though he was questionably not pursued in free agency.

With no new faces this year, the Red Sox already have lost Carson Smith to season-ending surgery and have yet to get Tyler Thornburg back from surgery he had to treat thoracic outlet syndrome.

Still, the Sox bullpen entered yesterday ranked third in the American League and sixth in MLB with a 2.98 ERA.

“We’re lucky just because it’s something that, all around we have good hitting and defense, good starting pitching and a good bullpen,” said Joe Kelly, who has a 2.70 ERA. “Looking around the league, not to knock other teams, but you see other teams and guys coming in from their bullpen and you’re like, ‘Wow, we are lucky to have so much talent on our team and in our bullpen.’

“There are good arms in our Triple-A system that can’t even get up here because we have so many good pitchers on our team. You see other teams and you’re like, ‘All these guys can pitch on other teams right now.’ It’s cool to see. It’s just how it was built and got put together. It’s one of those lucky draws.”

Just in the last two weeks, as the Red Sox were already without Smith and then put Drew Pomeranz on the disabled list, they called up Brandon Workman from Triple-A Pawtucket.

The 29-year-old had a 3.18 ERA last year, his first since recovering from Tommy John surgery, and was dominating for the PawSox with 30 strikeouts to just five walks in 28 innings.

“I told these guys in spring training, there are a lot of guys that are going to be here that didn’t start the season that are going to contribute,” said manager Alex Cora. “So far if you look at the guys who have contributed, Marcus Walden, Bobby Poyner, Workman — that’s part of the equation.

“I felt good coming into the season with our pitching staff, our relievers. I felt last year that was a strength of the team. Although they’re similar, they’re different.”

It made it easy to move knuckleballer Steven Wright from the ’pen to the rotation when Pomeranz got hurt knowing there was more depth behind him.

Workman has allowed just two hits and a walk while striking out five over 51⁄3 innings since being recalled.

“This is a different pitcher compared to early in spring training,” Cora said. “There’s a reason he didn’t make the team, let’s put it that way. His velocity was down, his breaking ball wasn’t there, his tempo wasn’t good. Now, even though he’s not throwing 94-95 mph, 91-92 mph is good enough. His cutter is good. The breaking ball has been outstanding. You saw it yesterday, he came in in an important situation for us and got those outs. We’re very pleased with the way he’s throwing the ball.”

Three months into the season, it’s looking as if the starting pitching will be the lifeblood of the Red Sox. But even as the rotation ERA has fallen from second in the majors in ERA early in the year to eighth (3.68 ERA as of yesterday), the bullpen has made up the difference.

Craig Kimbrel (2.48 ERA), Kelly and Matt Barnes (2.43 ERA) have been mostly dominant in the late innings while Hector Velazquez (1.93 ERA) has surprised in a versatile role.

Sox relievers have allowed just 19 homers, third-fewest in the majors, while opponents put the ball in play just 16 percent of the time, the third-lowest.

“Everyone has a good idea of when they’re going to pitch for roles, so it makes it easier to succeed,” Kelly said. “You can read the score, for our long guys to late inning guys to parts of their lineup, guys who have been used. Just letting people know ahead of time or maybe after the first week, roles are defined and you know.

“As long as roles aren’t changing it’s going to make everyone in that bullpen more successful rather than getting thrown in randomly without having stretched or gone through your routine, then there’s a chance for failure.”