Pirates address bullpen in a big way by adding Luke Weaver, Kirby Yates and Lake Bachar

MILWAUKEE -- The Pirates’ desire to improve their bullpen defined their deadline day, as they added Luke Weaver from the Mets, Kirby Yates from the Angels and Lake Bachar from the Marlins on Monday afternoon.

The Weaver deal -- the headliner of everything the Pirates did -- cost them High-A shortstop Sammy Stafura, who was ranked No. 9 by MLB Pipeline.

Weaver, 32, is having an excellent season, despite the Mets struggling as a team. He’s 2-1 with a 1.84 ERA in 42 appearances, walking 11 and striking out 45 in 44 innings. Opponents are hitting just .162 against Weaver, who has a 0.82 WHIP.

MLB Trade Rumors ranked Weaver as the third-best relief option behind Mason Miller and Adrian Morejon from the Padres -- two pitchers who probably aren’t even available considering San Diego has won eight of its past 10.

The Pirates have needed right-handed relief help, hence Saturday’s deal for Camilo Doval, and few do it better than Weaver, who has allowed just one earned run over his last 30 appearances.

That also framed why they added Yates and Bachar right before the buzzer.

Yates has a 3.95 ERA in 31 appearances with Los Angeles, walking 12 and striking out 36 in 27 1/3 innings. He’s a two-time All-Star who’s 39 years old and has pitched for seven teams over 12 seasons, saving 41 games for the Padres in 2019.

Bachar, meanwhile, is in his third pro season and has a 3.88 career ERA in Miami. He’s been a valuable piece for the Marlins this season while working 58 2/3 innings and pitching to a career-best 3.84 ERA. Bachar has walked just 21 while striking out 21.

To acquire Bachar, the Pirates gave up Triple-A right-hander Brandan Bidois, who saw big league time this season; High-A Greensboro Brian Sanchez; and Florida Complex League shortstop Hyun Seung Lee. They traded Double-A Altoona right-hander Kyle Robinson to acquire Yates.

None of the four players are ranked in the Pirates' top 30, according to MLB Pipeline.

It'll be interesting to see how the Pirates use their three new relievers, but this much is clear: That group got much better and deeper on Monday.

Their mix -- at least for now -- figures to include Gregory Soto, Mason Montgomery, Weaver, Camilo Doval, Yohan Ramirez, Yates, Bachar and Carmen Mlodzinski. Evan Sisk is expected return Tuesday and should factor into the mix.

As for Weaver, this season righties are hitting just .099 against him and have a .322 OPS. That’s the lowest mark among Major League relievers (minimum 70 at-bats), while Weaver’s numbers against lefties (.225 and .625) are still quite good.

Weaver’s ERA is tied with Atlanta’s Didier Fuentes for the sixth-lowest mark among MLB relievers who’ve worked at least 44 innings. When comes to batting average against, only five MLB relievers have a lower mark (minimum: 150 at-bats).

In addition to the Mets, Weaver has pitched for the Yankees (2023-25), Mariners (2023), Reds (2023), Royals (2022), Diamondbacks (2019-22) and Cardinals (2016-18), posting a 4.58 ERA and 791 strikeouts in 312 career games (106 starts).

After bouncing around as a starter/swingman type, injuries eventually caught up to Weaver, and he found success as a short-stint reliever toward the end of the 2023 season.

Over the past three years, Weaver has been among the most dominant relievers in MLB, his 2.90 ERA in 168 appearances ranking fifth-lowest among all MLB relief pitchers with at least 190 innings pitched.

Similar to Doval, Weaver has ample playoff experience, pitching in 15 postseason games. In 2024, when the Yankees reached the World Series, Weaver went 1-0 with four saves, a 1.76 ERA, 16 strikeouts, a .163 batting average against and 0.65 WHIP.

Weaver throws a four-seamer 49.7% of the time, his changeup at a 34.9% clip and cutter 15.2%. All three have been effective, with the heater averaging 95.3 mph. Opponents are hitting just .186 against that pitch, while they’re slugging just .234 on Weaver’s changeup.

This season has been especially dominant for Weaver, as he possesses the second-best swinging-strike rate (14.4%) of his career. He’s also working off of a career-best chase rate (34.2%), which will help a Pirates bullpen that needs to throw more strikes and miss more bats.

Weaver has been used primarily as a setup man, though he will almost assuredly see closing opportunities in Pittsburgh.

Stafura was acquired last year in the Ke’Bryan Hayes deal. Not only did the Pirates shed the remainder of Hayes’ contract, but they turned that into an impressive shortstop prospect — and Stafura got even better this year.

In 46 games with High-A Greensboro, Stafura hit .302 with an 1.029 OPS that includes seven doubles, a triple and 19 home runs. July was a constant heater for Stafura, who hit .358 and bashed 14 home runs. Nobody in baseball — Majors or Minors — had more.

But with the Konnor Griffin entrenched at the MLB level, it made sense to deal from a position of strength.

It was rumored that the Pirates were in a bidding war for Weaver with the Milwaukee Brewers — ironic because the teams will meet for a four-game series starting Monday at American Family Field.

Weaver is making $8 million this season, but the Pirates will only be responsible for a prorated portion of the league minimum (roughly $238,000). He’s due $11 million next season, but the Mets will pay $6 million as part of the deal.

This story will be updated.

Jason Mackey: Jason.Mackey@pirates.com and @JMackey_PGH on X.