PHOENIX -- It’s been quite an offseason for the Arizona Diamondbacks, who swooped in two days before Opening Day to pick up the last big name remaining on the free-agent market, agreeing to a deal with left-hander Jordan Montgomery and then officially announcing it Friday afternoon.

The contract is for one year and is worth $25 million, a source told MLB.com's Mark Feinsand, and it includes a vesting option for 2025.

If Montgomery starts 10 games this year, his 2025 contract option will vest at $20 million. If he makes 18 starts the vesting option is worth $22.5 million, and if he makes 23 starts or more it vests at $25 million.

Montgomery can also opt out of the deal for 2025 if he makes 10 starts in 2024.

Both D-backs GM Mike Hazen and manager Torey Lovullo said they were unable to talk about the deal during media availability on Wednesday.

First baseman Christian Walker -- who played with Montgomery at the University of South Carolina -- however, praised the move.

“Super excited to be back in the locker room with him,” Walker said. “I know he's a pro and he's gonna fit right in with the guys. You know obviously the talent and the skill set is there but [knowing] his mentality and his personality, too, makes it exciting.”

Bringing in Montgomery gives Arizona a fearsome top of the rotation alongside Zac Gallen and Merrill Kelly, and it also gives them some insurance in the event Eduardo Rodriguez, their other big pitching pickup from this offseason, has to miss extended time with a lat issue.

Rodriguez suffered the lat injury last week in a game against the Cubs. How long he will be out is not known at this point, but he will open the season on the injured list.

Montgomery reportedly has been throwing live batting practice sessions, but it’s not known when he would be able to realistically pitch in the regular season.

Until Montgomery is ready and Rodriguez is healthy, the D-backs' rotation is currently aligned to go Gallen, Kelly, Tommy Henry, Brandon Pfaadt and Ryne Nelson.

Montgomery bolstered his free-agent stock with a stellar year in 2023, registering personal bests in ERA (3.20), strikeouts (166) and innings (188 2/3) over 32 starts between the Cardinals and Rangers in his age-30 season.

The 6-foot-6 lefty was especially effective after joining Texas in a Trade Deadline deal, pitching to a 2.79 ERA over 11 starts in the regular season and rising to the occasion in the playoffs. He went 3-1 with a 2.90 ERA in six postseason appearances (five starts), helping the Rangers win the first World Series in franchise history.

It was the second straight year he was dealt at the Deadline, as he went from the Yankees to the Cardinals in a 2022 swap for center fielder Harrison Bader.

A fourth-round Draft pick by the Yanks in 2014, Montgomery made his big league debut for the Bronx Bombers in 2017 and finished that year with a 3.88 ERA over 29 starts.

The South Carolina native missed most of the next two seasons while recovering from Tommy John surgery and posted a 5.11 ERA over 10 starts during the shortened 2020 campaign, but he got his career back on track for New York in 2021.

Montgomery has put together three straight seasons with at least 30 starts, notching a collective 3.48 ERA with a 3.6 K/BB ratio over 94 starts in that span.