Mariners Analysis: Is Nate Karns the Odd Man Out in Seattle?


What kind of role will Nate Karns play next season with the Mariners following the signing of Hisashi Iwakuma?

As many of you are aware, the Seattle Mariners re-signed Hisashi Iwakuma after his deal with the Los Angeles Dodgers fell through on Thursday. Mariners’ fans are delighted to welcome Kuma back to the Pacific Northwest. However, one person who likely is less excited is Nate Karns.

The 28-year-old right-hander was acquired in November from the Tampa Bay Rays. In fact, he was the centerpiece of the deal that saw Logan Morrison, Brad Miller and Danny Farquhar go to the Rays. Karns was expected to be the caboose in the M’s rotation prior to the signing of Iwakuma, but now his role is in question.

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Originally selected in the 12th round of the 2009 draft by the Washington Nationals, Karns reached the big leagues in May of 2013. He struggled in limited action with the Nats, going 0-1 with a 7.50 ERA across 3 starts. He struck out 11 and walked 6 through 12 innings. Karns was sent to Tampa Bay following the season as part of the return package for Jose Lobaton.

Karns spent the bulk of the 2014 season with the Rays’ AAA affiliate in Durham, but he fared reasonably well during his brief look in Tampa. He went 1-1 while posting a 4.50 ERA through 2 outings. Karns struck out 13 and walked 4 across 12 innings pitched. Karns held the opposition to just 0.917 hits/walks per inning.

The Texas Tech alum entered the 2015 season with a spot in the Rays’ starting rotation. Karns made the most of his opportunity last season, going 7-5 and registering a 3.67 ERA in 27 appearances. He fanned 145 and issued 56 free passes through 147 innings. It was the definition of a breakout campaign, as Karns tallied 2.2 wins above replacement.

Karns also has a strong track record during his minor-league career. He has gone 33-21 with a 3.45 ERA across four seasons in the junior circuit. Karns has rung up 515 hitters while walking 190 through 449.1 innings. He has limited the opposition to 1.202 walks/hits per inning, and has allowed just 0.7 home runs per 9 innings.

Baseball Reference is projecting Karns to have a solid season for the Mariners in 2016. They are predicting he will go 7-6 with a 3.92 ERA in 133 innings of work. The brainiacs over at FanGraphs are equally as optimistic about Karns in 2016. They expect he will post a record of 7-8 with a 4.07 ERA across 23 starts.

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As of December 18, the Mariners’ starting rotation appears to be set with Felix Hernandez, Hisashi Iwakuma, Wade Miley, Taijuan Walker and James Paxton. That is a formidable starting five, and should be considered amongst the best in the American League West. However, Karns appears to be on the outside looking in.

The Mariners could opt to move Karns to the bullpen, but he has made just 7 relief appearances as a professional. He does have minor-league options remaining, and thus he could start the season in Tacoma with the Rainiers. The Mariners were thought to be shopping Paxton earlier in the offseason, and they could clear a spot for Karns by moving Pax-Man.

If the season were to start today, I imagine Nate Karns would be pitching for the Tacoma Rainiers. The Mariners will likely give him an opportunity to compete with James Paxton for the final spot in the rotation next spring, but Pax-Man has to be viewed as the heavy favorite. I don’t see Seattle trading Paxton this offseason.

Next: Seattle Mariners Re-sign Hisashi Iwakuma

The Mariners are very lucky have an excess of talent in their starting rotation. Kuma and Paxton are both very fragile hurlers, and Karns provides the M’s with invaluable depth. I fully expect Karns to pitch significant innings in 2016 working out of the bullpen, as spot starter or filling in for an injury.