BALTIMORE — The first domino in a potentially busy Trade Deadline season for the Orioles has fallen, and it was a move that not many may have seen coming.

On Friday, Baltimore dealt veteran outfielder Austin Hays to Philadelphia in exchange for right-hander Seranthony Domínguez and outfielder Cristian Pache. The trade between two of the top teams in baseball — the MLB-best Phillies (64-38) and the American League East-leading O’s (61-41) — addressed needs for both sides.

The Orioles are expected to be quite active in the pitching market to bolster both their rotation and bullpen, and Domínguez should help with the latter. The 29-year-old righty has a 4.75 ERA in 38 relief appearances this season, but he’s been better in the past, recording a 3.55 ERA over 230 career MLB outings.

Domínguez also has high-octane stuff. His four-seam fastball is averaging 97.6 mph this year, which ranks in the top 5% of MLB, per Statcast. He also has postseason experience, having pitched to a 1.13 ERA in 15 career playoff appearances over the past two seasons.

Last year, Domínguez tossed 5 1/3 scoreless innings during the Phils’ run to the NL Championship Series.

In order to land Domínguez, Baltimore parted with one of its veteran leaders in Hays.

An All-Star in 2023, Hays was one of the pre-rebuild mainstays for the Orioles, along with fellow outfielders Cedric Mullins and Anthony Santander. The 29-year-old Hays played seven seasons for Baltimore, compiling a .263/.315/.433 slash line in 557 games.

This season, Hays started slow, as he was batting .111 with a .311 OPS when he went on the injured list with a left calf strain on April 22. Since returning in mid-May, he’s mostly served in a platoon role — starting in left field against left-handed starters — and has thrived, slashing .313/.363/.509 with 13 doubles, three homers and 12 RBIs in 44 games.

Pache should give Baltimore some right-handed outfield depth in Hays’ absence. The 25-year-old is a former top prospect who has slashed .179/.243/.272 in 213 games over five big league seasons with the Braves, A’s and Phillies. This year, he has hit .202 with a .557 OPS in 50 games for Philadelphia. He can also play all three outfield positions.

However, don’t expect Pache to take over Hays’ role. By moving Hays, the Orioles have potentially opened up more playing time for young players such as Heston Kjerstad and Connor Norby (the club’s No. 5 prospect per MLB Pipeline).

Kjerstad should get more time in left, although Baltimore can also start Colton Cowser, Mullins and Santander from left to right in the outfield. First baseman Ryan O’Hearn has also made six appearances in left this year. And Norby hasn’t yet played outfield in the Majors, but he made 26 starts in left field for Triple-A Norfolk this season.

The Orioles’ position-player roster now has less right-handed thump. But that could be fixed in the near future with first baseman/third baseman Coby Mayo (the club’s No. 3 prospect and MLB Pipeline’s No. 15 overall) nearing his first MLB callup.