The Yankees Snapped Up This Offseason’s Best Pitcher And he might get better in pinstripes.

The New York Yankees tried to trade last winter for Gerrit Cole, arguably the top starting pitcher available. They were not willing to to meet the Pittsburgh Pirates’ asking price. Cole landed in Houston. Who knows how he might have changed the Yankees’ 2018 season.

This offseason, the Yankees again targeted the top pitcher available. This time, they got him.

The Yankees acquired left-handed pitcher James Paxton from the Seattle Mariners on Monday evening for a package of three prospects. While he might not be a household name outside the Pacific Northwest, he offers the Yankees the potential for a second legit ace alongside Luis Severino.

Paxton ranks near the top of the leaderboard in nearly every rate statistic that indicates pitcher dominance. Since his breakout 2017 season, Paxton ranks sixth in the majors in strikeouts per nine innings (11.1) among pitchers who have thrown at least 150 innings, sixth in strikeout percentage minus walk percentage (23.8 percent) and eighth in wins above replacement per 200 innings (5.7) — a rough measure of what a healthy starting pitcher might provide over a full season — trailing starters Chris Sale, Max Scherzer, Jacob deGrom, Corey Kluber, Noah Syndergaard and Severino, plus reliever Blake Treinen, who got a lot of work in last year. In other words, the elite of the elite. He ranks seventh since 2017 in fielding-independent pitching (2.95), which is scaled like ERA but factors out how the defense affects pitchers’ stats, and 34th by a more traditional measure, ERA (3.40).

Is it enough to close the gap with the reigning World Series champions, the Boston Red Sox?

Yankees GM Brian Cashman said adding Paxton may be just a start.

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

And the same way Cole improved with the Astros last season, the Yankees might also be acquiring a pitcher who could get better in his new home. Even a home as hitter-friendly as Yankee Stadium.

The Yankees prize velocity. They led the majors with an average fastball of 95.3 mph last season, and the three hardest-throwing staffs of the pitch-tracking era (since 2007) have played in pinstripes. Paxton’s fastball averaged 95.9 mph last season, ranking 15th among pitchers that had thrown at least 100 innings (Severino was second at 97.9 mph).

Paxton has one of the game’s top whiff rates (26.1 percent on pitches that drew a swing) on his fastball and he also allows some of the weakest contact in the game. The average exit velocity of balls batters made contact with against him (89.4 mph) ranked in the lowest 4 percent. Here’s an elevated 97 mph fastball that Paxton threw for his 15th strikeout in a May game against the Oakland A’s:

But although the Yankees like elite fastballs and Paxton has a good one, New York ranked just 16th in four-seam fastball usage last year. The team often uses velocity to set up breaking balls and changeups, which tend to get more swings and misses than fastballs do. And with this strategy, the 2018 Yankees became just the third staff ever to strike out more than 10 batters per nine innings (10.10), joining the 2017 Cleveland Indians (10.08) and 2018 Astros (10.44).

So it won’t be a surprise if the Yankees help Paxton by getting him to rely on his fastball less. Paxton threw it 55.6 percent of the time last season, ranking 26th in usage in the majors.

Paxton’s cutter ranked second in the majors, behind Trevor Bauer, in whiffs per swing, at 37.2 percent.

Opponents hit .145 versus Paxton’s cutter and .235 against his curveball, including this whiff against Josh Donaldson during a no-hitter Paxton threw against the Toronto Blue Jays in Canada, where he grew up:

He could benefit from using those offspeed and breaking pitches more often, and he might have a fourth pitch if he keeps to his plan to incorporate a changeup.

“Oh, I’ve seen it,” Mariners starter Wade LeBlanc told The Athletic in September. “If he were to throw that pitch in games, it would be the best [changeup] on the team.”

The problem with Paxton is less quality than quantity. The ace, who is under club control through 2020, doesn’t always contribute volume, as he’s often on the disabled list.

He has never thrown 200 innings in major league season, and his 160.1 innings last season were a career high. He’s dealt with an assortment of injuries, including a forearm bruise this past season. So for the Yankees, he’s not without risk, but the asking price wasn’t as steep as it was Cole.

The Yankees did part with left-handed pitcher Justus Sheffield, their No. 1-ranked prospect, according to Baseball America and FanGraphs. Sheffield was acquired in the 2016 midsummer trade that sent reliever Andrew Miller to Cleveland.

But Sheffield isn’t the same quality of prospect that Yankees infielders Gleyber Torres or Miguel Andujar were a year ago, according to some analysts, when the Pittsburgh Pirates demanded one of them in exchange for Cole. Some evaluators believe Sheffield might end up becoming a bullpen arm. Others see him as a mid-rotation starter. Sheffield has talent but his command issues continued in 2018. The Mariners might see more potential to work with in Sheffield, and the team also received powerful righty Erik Swanson and outfielder Don Thompson-Williams.

After selling his most valuable asset, Mariners GM Jerry Dipoto told reporters that the team plans to take a “step back” in 2019 and then take “two steps forward” later, with a focus on 2020 and 2021.

That’s an optimistic assessment.

The Mariners faded from playoff contention last season, and their average hitter last year was 29.8 years old, tying them with the San Francisco Giants for the oldest position players in the majors. (Their pitching staff was the 10th oldest at 29.0 years). By some measures, they have the game’s weakest farm system. The Mariners depleted their farm in recent years to upgrade the major league roster, but they have not advanced to the postseason since 2001, the longest drought in the majors. They might be waiting a while longer. As for the Yankees, who won 100 games last season but finished eight games behind Boston, a healthy Paxton will help them close the gap in the AL East.

The Yankees starters were fifth in WAR last season and tied for ninth in ERA-, which accounts for park effects and the league run environment. Paxton provides a massive upgrade from New York’s weakest link in Sonny Gray (5.26 ERA). The Yankees’ staff was already good, and now it might be great.