Seattle Mariners: Kyle Lewis was solid, but don’t overlook Justus Sheffield

Seattle Mariners starting pitcher Justus Sheffield quietly put together a very impressive rookie season.

For the Seattle Mariners, 2020 proved to be a productive season on many levels. Not only were the Mariners in playoff contention until very late in the season, but a number of young players took notable strides in their development as Seattle prepares to take the next step as an organization.

Outfielder Kyle Lewis is the favorite to take home American League Rookie of the Year honors after slashing .262/.364/.437 with a team-leading 11 home runs and 1.7 Wins Above Replacement, Yusei Kikuchi built on his disappointing rookie season, and even without a minor league season, prospects Jarred Kelenic, Logan Gilbert, Julio Rodriguez, and others made a lot of noise at Seattle’s Alternate Site.

The Seattle Mariners are a team on the rise, loaded with notable prospects and in a division prime for the taking with a few key moves.

While much of the attention was deservedly on Kyle Lewis and his debut campaign, let’s not overlook the season starting pitcher Justus Sheffield put up for the Seattle Mariners.

Sheffield ditched his four-seam fastball, a pitch he just about 48% of the time in 2019, for a sinker and pounded the strike zone more frequently in 2020, resulting in a very impressive year for the 24-year-old.

In 10 starts for the Mariners, Sheffield went 4-3 with a 3.58 ERA (3.17 FIP), a 1.30 WHIP, and .249 average against. He was worth 1.6 fWAR which led all American League rookie starting pitchers in 2020.

Sheffield relied a little less on strikeouts (20.7% K-rate), but he dropped his walk rate from nearly 11% to 8.6% this season and kept the ball on the ground more than 50% of the time. In 55.1 innings of work, Sheffield allowed just two home runs, this after allowing five in 36 innings last season with the Mariners.

In six of Sheffield’s 10 starts he went at least six innings and allowed two or fewer earned runs. After giving up six earned runs and failing to make it out of the fifth inning in an August 29th start against the Los Angeles Angels, Sheffield ended the year by giving up just six earned runs across his final four starts (25 total innings).

While Kyle Lewis and Luis Robert flashed the leather and entertained us with plenty of home run bombs, and Baltimore Orioles rookie Ryan Mountcastle made a strong case for Rookie of the Year votes with his half-season of play, Justus Sheffield equally deserves to be in the conversation for ROTY honors with his performance.

More importantly, Sheffield appears to be a rotation arm the Seattle Mariners can rely on as they head into 2021 and beyond. With Emerson Hancock, Logan Gilbert, and George Kirby all waiting in the wings down on the farm, the Mariners should be optimistic about their rotation moving forward.

Don’t overlook these Seattle Mariners. It won’t be too long before they are making some noise as a playoff-worthy team.