Diamondbacks 2023 Player Reviews: Kyle Nelson

The sophomore left-handed reliever experienced a variety of highs and lows as he navigated a full-time bullpen role

This article is part of a series of player reviews for the 2023 Arizona Diamondbacks. It was a surprising and marvelous year for the team as they won 84 games to make the postseason. They advanced all the way to Game Five of the World Series before bowing out to the Texas Rangers. There are 54 players in all that had at least one at-bat or pitched at least one inning for the team this past season. They are being presented in reverse order of their aWAR (average WAR-Wins Above Replacement) produced, which is the average of Baseball Reference and Fangraphs WAR. These are their season stories.

Kyle Nelson had a great first half, rough second half en route to an average 2023 / Jake Oliver

Kyle Nelson's first full season as an MLB reliever is in the books. It was a solid season that should've had far better full-season stats had it not been for a tough final month or so of the regular season. Nelson made his first Opening Day roster and started hot. He had just one run allowed with three walks and 15 strikeouts in 12 games to conclude April. His ERA was 0.82 while he had a 2.80 FIP.

May wasn't nearly as strong as April. Of his 13 appearances, he allowed a run in five of them. His monthly ERA was 4.66 while his FIP was 5.12 indicating he was lucky to have an ERA that low. He did strike out 10 batters to just four walks in 9.2 innings, but opponents were hitting .314 against him.

In June, Nelson got back on track and regained his April form. Over 10 games and 10 innings, Nelson allowed just three runs and struck out 14 batters to only two walks. His ERA was 2.70 while his FIP was a sparkling 2.36. That indicates he was unlucky to a degree to have "that high" an ERA.  

July was slightly worse than June, but was still quite good for a reliever that was working in an overtaxed bullpen. Nelson had 13 games and 10.1 innings. He finished the month with a 3.48 ERA and 4.32 FIP with zero walks and 14 strikeouts. It continued his impressive run of limiting walks and striking out more than a batter per inning. This was indicative of a strong year for the left-handed reliever.

However, August started the turn for the worse for the capable young left-handed bullpen arm. While he made 11 appearances, only two were truly disastrous. In the other nine games and seven innings, Nelson allowed zero runs or walks, and struck out six batters. However, in both of his August 9th and 24th outings, he gave up two runs, a walk or two, and multiple hits. He didn't get a single out in the 9th inning.

In September, Nelson came fully unglued with four outings in which he allowed at least one run and three times giving up three runs. That tanked his season-long stats despite having good secondary numbers. The biggest issue in those 7.1 innings and nine games was the home run. He gave up four of them as he struggled to locate his slider. His ERA was an ugly 11.05 with a 9.53 FIP. He allowed 12 hits and 10 runs with just six strikeouts.

Still, his base season stats aside from his ERA and FIP were quite good. He struck out 10.8 batters per nine innings, over three batters higher than his 2022 numbers. He walked only 2.3 batters per nine, a stark drop from his 22' numbers. His xERA was a good 3.87 while his xFIP was a stronger 3.56. Nelson simply struggled from the long-ball. In nearly every single one of his truly bad outings, he gave up a home run. If he can avoid misplacing his slider or fastball, Nelson is a lethal left-handed weapon out of Manager Torey Lovullo's bullpen.

In the playoffs, Nelson pitched five times,  but once again struggled with giving up the home run. He gave up two of them in just five innings. Overall though, he allowed just two earned runs while walking two and striking out one. He was lucky to not give up more damage as his FIP (9.26) indicated he should've.

2024 Status and Outlook:

Kyle Nelson is entering the off-season knowing he likely has a job on next season's Opening Day roster as a bullpen arm. He and Andrew Saalfrank are among Arizona's top left-handed relievers. So long as Nelson does not have a very poor Spring Training, his spot is secure. The 27-year-old still has another season to go before entering arbitration. His 2024 salary will be slightly above the minimum salary in MLB. Beyond that, the D-backs control his rights until 2028.  Unless the home run issues persist and become chronic it's likely safe to say that Nelson is a Diamondbacks player for the foreseeable future.

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