Mariners starting pitcher James Paxton delivers against the Yankees at...

Mariners starting pitcher James Paxton delivers against the Yankees at Yankee Stadium on June 21. Credit: Kathleen Malone-Van Dyke

Time to give thanks, Yankees fans.

In the first of what could be multiple top-of-the-rotation offseason additions, the Yankees acquired lefthander James Paxton from the Mariners on Monday night, giving up three prospects, including highly touted lefthander Justus Sheffield.

The Yankees hope Paxton can help solidify their rotation by offering what their other starters did not, at least not for the entirety of 2018: high-end production from a high-end arm.

“He’s establishing himself as a real quality lefthander in the game today, and obviously doing it within our league,” general manager Brian Cashman said. “It’s nice to add him to the mix of what we already have. We have a talented pitching staff and I think he’s going to provide some more impact into that staff. But I need to add to him.”

Paxton comes with a caution sign: questionable durability, as shown by seven trips to the disabled list since 2014. His 3.76 ERA and 1.10 WHIP in 2018 came in 28 starts and 160 1/3 innings — both career highs. He spent time on the DL with lower back inflammation and a left forearm contusion.

Although he’s never been an All-Star or received a Cy Young vote, Paxton, 30, has long been thought to have a very high ceiling. He was a top-100 prospect circa 2012-14. But that injury history has contributed to his inability to fulfill  his potential.

Cashman said the Yankees were encouraged by Paxton “continuing to trend in the right direction,” including jumping from 20 major-league starts in 2016 to 24 in ’17 to 28 in ’18. He was 11-6 in 2018 and 23-11 the past two seasons.

“I continue to try to work toward being healthy for an entire season,” Paxton said. “I feel like I’ve been lucky I haven’t had any really bad injuries as far as elbow, shoulder, that kind of stuff. The good news so far has been that all the injuries I’ve had haven’t reoccurred. I’ve learned how to make sure those things don’t happen again through exercise or whatever.”

Said Cashman: “He passed our medical review and we’re excited to welcome him to the Yankee family.”

Paxton, a member of the Mariners' organization since the 2010 draft, made news in May when he no-hit the Blue Jays in Toronto, becoming the first Canadian-born pitcher to accomplish that feat on Canadian soil. Listed at 6-4 and 235 pounds, Paxton is nicknamed “Big Maple.”

A veteran of parts of six big-league seasons, Paxton is under control through the 2020 season. He made $4.9 million in 2018 and is due for a raise via arbitration this winter.

Paxton throws a four-seam fastball that averages 96 mph and a sinker at about that velocity, according to Brooks Baseball, plus a curve and a cutter.

That repertoire helped Paxton become one of the preeminent strikeout pitchers in the majors. Among hurlers with at least 160 innings in 2018, Paxton, who struck out 208 batters,  ranked fourth with a 32.3-percent strikeout rate, right behind Justin Verlander, Max Scherzer and Gerrit Cole.

Cashman has been open about his desire to add multiple starting pitchers — beyond re-signing CC Sabathia — to bolster the Yankees’ rotation behind Luis Severino and Masahiro Tanaka. Paxton helps satisfy that need.

In 2018, Severino made 32 starts — the only Yankee to make more than 29 — but had a 5.57 ERA in the second half (3.39 ERA overall). Tanaka had a 3.75 ERA in 27 starts.

“We’ve got one in the fold,” Cashman said. “And at the very worst we’re looking to add another.”

In addition to Sheffield, the Yankees sent righthander Erik Swanson and outfielder Dom Thompson-Williams to Seattle.

Sheffield, 22, was considered the Yankees’ top prospect — he is ranked No. 31 in baseball by MLB Pipeline — and touched the majors in 2018, getting into three games as a reliever. A starter by trade,  Sheffield had a 2.48 ERA and 1.14 WHIP in 25 games (20 starts) for Double-A Trenton and Triple-A Scranton/Wilkes-Barre.

The other two minor-leaguers are secondary pieces. Swanson was ranked as the Yankees’ No. 22 prospect and Thompson-Williams was not ranked in the top 30.

Swanson, 25, reached Triple-A last season, posting a 3.86 ERA and 1.07 WHIP in 14 games (13 starts) after dominating for Trenton (0.42 ERA, 0.87 WHIP in eight games).

Thompson-Williams, 23, is a bit of a wild card. A 2016 fifth-round draft pick, he posted solid power numbers — .546 slugging percentage, 22 homers, 17 doubles, four triples — across two Class A  levels in 2018. He batted .299, had a .363 OBP and played primarily centerfield.

Still on the Yankees’ to-do list, per Cashman: at least one more starter, a middle infielder and bullpen help.

“I got a lot of heavy lifting to do,” he said. “This is one example of the work to be done.”

More Yankees headlines