Jordan Yamamoto of the Miami Marlins pitches against the New...

Jordan Yamamoto of the Miami Marlins pitches against the New York Mets at Citi Field on Aug. 7, 2019. Credit: Jim McIsaac

Still aiming to improve their pitching depth, the Mets acquired righthander Jordan Yamamoto from the Marlins on Monday in exchange for minor-league infielder Federico Polanco.

Yamamoto, 24, was designated for assignment by Miami — which has an abundance of young, controllable starting pitchers — last week. In limited major-league experience, Yamamoto was a serviceable rookie in 2019, posting a 4.46 ERA and 1.14 WHIP in 15 starts — but in just four games last year had an 18.26 ERA.

Yamamoto can be optioned to the minors and thus affords the Mets the kind of flexibility that they have desired in acquiring certain players this offseason. He won’t be eligible for arbitration until after the 2022 season and isn’t scheduled to be a free agent until after the 2026 season at the earliest.

Deepening their pool of starting pitchers has been a goal for the Mets this offseason.

Jacob deGrom, Carlos Carrasco (acquired via trade last month) and Marcus Stroman (re-signed in November) figure to fill out the top of the rotation. David Peterson, off a strong rookie showing in 2020, seems like a safe bet for a back-end rotation spot. That appears to leave the fifth-starter job up for grabs heading into spring training — unless, of course, they add another established starter such as Trevor Bauer, who remains a free agent.

Steven Matz, traded to the Blue Jays last week, is no longer a factor. Yamamoto joins a group of depth starters that includes lefthander Joey Lucchesi and righthanders Sean Reid-Foley, Corey Oswalt and Franklyn Kilome. Also, the Mets have not ruled out Seth Lugo or Robert Gsellman as rotation candidates.

Polanco, headed to Miami, doesn’t have much prospect status, a .244 hitter across two minor-league seasons. He turns 20 next month and hasn’t played beyond rookie ball.

To make room for Yamamoto on the 40-man roster, the Mets designated infielder Robel Garcia for assignment. They claimed Garcia, 27, off waivers from the Reds in October — under the previous front office and ownership.