Mariners’ brass expect big step forward for Justus Sheffield in 2020

One of the Mariners’ first big moves in their rebuild ahead of the 2019 season was trading left-handed starter James Paxton to the New York Yankees in exchange for a trio of prospects, with the prize being then-top-100 prospect Justus Sheffield, a left-handed pitcher.

Mariners manager Servais explains how he’ll measure success in 2020

Even with a flurry of moves acquiring elite prospects, Sheffield was still considered one of the best prospects in Seattle’s farm system, if not the best, but ended the season outside of MLB Pipeline’s top-100 list for the first time in years after he struggled while other Seattle prospects shined.

Sheffield, now 23, opened 2019 in Triple-A Tacoma and, like most pitchers in Triple-A last year, did not fare well. In 13 games with the Rainiers, Sheffield had a 6.87 ERA, 1.818 WHIP and gave up 41 walks while striking out 48 in just 55 innings.

A demotion to Double-A Arkansas saw Sheffield get into a groove, tossing 78 innings with a 2.18 ERA and struck out 85 batters while walking 18. His WHIP also went down tremendously to 1.026. He ended the season with the Mariners and in 36 innings, Sheffield’s ERA was 5.50, his WHIP was 1.722 and he struck out 37 while walking 18.

It’s expected that Sheffield will open the season as one of the Mariners’ five starting pitchers for a club that will feature a number of young players who are getting their first extended looks at the major league level. Based on what manager Scott Servais and general manager Jerry Dipoto told 710 ESPN Seattle’s Danny and Gallant this week, we should expect to see tremendous progress from the young lefty.

“Sheff looks great. And more importantly, he looks confident,” Dipoto told Danny O’Neil and Paul Gallant Monday. “He came in, he understands what’s in front of him and the opportunity … He came in focused (and) he’s thrown very well in the bullpen.”

Where Sheffield struggled, as evidenced in the numbers above, was with his command. If that improves, or is similar to where it was when he dominated in Double-A, his plus pitches will carry him far.

“Sheff’s got great stuff,” Dipoto said. “I mean physically, when he stands out there on the mounds and he’s throwing alongside our other starting pitchers, you quickly train to him. He moves fast, he’s got quick stuff … and we did see flashes last year … where he was able to show you a mature major league pitcher.”

Sheffield has a good fastball that will sit in the low- to mid-90s, touching as high as 97 and a decent changeup, but his best pitch by far is his slider.

“He looked great (this week),” Servais said on Wednesday. “I was really happy with how he went about it. He fell behind in the count to a couple guys, but he righted the ship, he got back in the count and then he’s got wipeout stuff and ended a couple at bats with really good sliders”

Servais agreed with Dipoto that Sheffield looks more confident, and along with that, he is much more comfortable than he was during spring training last year.

“Anytime you come over to a new ballclub, you don’t really know people,” Servais said. “‘How do I fit in? Who am I going to hang with away from the park?’ And going through what he went through last year having to go all the way back to Double-A kind of getting back on track with his command of his pitches. He’s always had good stuff, it was about getting it over the plate.”

Despite being drafted in the first round by the Cleveland Indians in 2014, Sheffield is still extremely young and Dipoto says the best is yet to come for the southpaw.

“It’s hard to remember Sheff as long as he’s been on the prospect scene, he’s still 23 years old and he’s going to pitch this year as a 24-year-old,” Dipoto said. “We feel there’s a lot in front of him and a lot of positives. So far this spring, he looks the part of a mature, ready for the major leagues pitcher.”

Servais also expects a lot from the lefty.

“He’s ready to take the next step.”

Listen to the full interviews with Dipoto and Servais here (Dipoto) and here (Servais).

Follow 710 ESPN Seattle’s Danny O’Neil and Paul Gallant on Twitter.

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