The deal: The Yankees acquire LHP James Paxton from the Mariners for LHP Justus Sheffield, RHP Erik Swanson and OF Dom Thompson-Williams.
Why the Yankees did it: Looking to bolster a rotation that ranked fifth in the American League in ERA in 2018, the Yankees added one of the premier left-handed pitchers in the majors -- and one of the few quality starters available on the trade market. Paxton had the second-highest fastball velocity among lefty starters in 2018, behind only that of Cy Young winner Blake Snell, while going 11-6 with a 3.76 ERA and 208 strikeouts in 160 1/3 innings. His strikeout rate of 32.2 percent ranked fifth among pitchers with at least 100 innings, and his 3.40 ERA the past two seasons ranks 22nd among pitchers with at least 250 innings.
When he's on, Paxton will just blow the fastball past hitters, jam right-handed batters with a cutter and pile up strikeouts with his curveball. He had a 16-strikeout game (in seven innings) and a no-hitter in back-to-back starts in early May. There's no doubting the quality of Paxton's stuff, but the knock against him is his durability. He has never qualified for an ERA title, and his 160 innings and 28 starts in 2018 were both career highs.
His injuries have mostly been of the nagging type; he had a short DL stint in August after getting hit on the forearm by a line drive and then missed a couple starts in September with a virus. His conditioning has been questioned, and his home run rate did spike from 0.6 per nine innings in 2017 to 1.3 in 2018, which largely explains the rise in ERA from 2.98 to 3.76. After a slow start in April (5.12 ERA), he had a 3.43 ERA the rest of the season while holding batters to a .219/.260/.375 line.