Seattle Mariners: What to expect from Justus Sheffield’s debut

Justus Sheffield will make his Mariners debut tonight, and it’s probably too early. but fun > logic sometimes, right?

When Yusei Kikuchi signed with the Mariners on New Year’s Eve, there was already a plan set in place for him. Jerry Dipoto and the powers that be set out a path for Kikuchi to limit his innings in a way that allows him to finish the entire regular season schedule.

The Mariners are approaching these inning limitations in an unorthodox way. Instead of blatantly skipping starts, Kikuchi will act as an opener once every fifth or sixth start of the season. This won’t happen too many times, as Kikuchi’s innings limit is seemingly somewhere around 150.

Today is the first of these handful of occurrences, and it’s generated a lot of intrigue. Not for Kikuchi, but for the pitcher scheduled to supplement him from the second inning on.

That would be Justus Sheffield, the consensus top prospect in the Mariners’ farm system. This comes as quite the surprise, with many (including us) expecting Sheffield to make his Seattle debut sometime in late May or June.

Those expectations were well warranted, given the nature of Sheffield’s first three starts for Triple-A Tacoma. For as highly touted as Sheffield has been, there have been real concerns about his command—particularly of his fastball—that have made him more of a projected #3 starter and nothing more.

Despite having an encouraging and impressive Spring Training with the Mariners, Sheffield struggled with his command once the regular season started. In 18.1 innings pitched, Sheffield walked 14 and struck out just 11. The culprit: his fastball command, once again.

It’s strange that the Mariners want to take a look at him this early. One would think it would be more beneficial to keep on his routine in Tacoma and let him figure things out. But Sheffield worked his fourth and final appearance for the Rainiers in an opener situation, in preparation for tonight’s game.

It was a similar story for Sheffield in that outing, walking three in the same number of innings of work. He allowed just one run, on a solo home run in the high altitude environment of Albuquerque, so that’s nice, but there’s still a cause for great concern.

Last night, the Mariners saw first-hand the nightmarish extremes of a pitcher’s debut with Rangers’ prospect Taylor Hearn. The hope is, of course, that Sheffield won’t share the same fate.

This isn’t, however, Sheffield’s first time at the MLB level. The 22-year-old lefty made his debut for the Yankees last year, appearing three times out of the bullpen. All but one of those outings went well for him, with the outlier being a three-run inning versus the eventual champion Boston Red Sox late in September.

It’s hard to imagine that Sheffield won’t struggle in some form tonight. There are real issues that need to be worked on that won’t suddenly fade overnight.

Expect Sheffield to try and go four innings tonight. It’s an unfavorable matchup for him on paper. The Rangers are a patient lineup, tied for 11th in walk percentage at a 9.7% clip. They can make Sheffield work, and if his command is still below-average then it could be a less than ideal night for him.

It may be Sheffield’s only outing in this current stint with the Mariners. The assumption is that, after tonight, Sheffield will be sent back down. It’s the smartest play, especially because the Mariners don’t have a spot in the rotation to give at the moment.

But tonight is a good opportunity to at least allow him to get his feet wet. And hey, it’s been a long time since the Mariners last called up a promising top prospect, so that’s pretty neat. #TeamFun keeps going strong.