Hits & Misses in Stat Predictions

In February, I predicted which players could have team leading statistics at the end of this season. Let’s look at what actually happened in games through 19 September. Stats were from Baseball Reference, FanGraphs, Baseball Savant, and the Fielding Bible.

Some stat leaders were mostly as expected.

Seth Beer led the team with 1.389 OPS & 267 OPS+, .444 ISO, 260 wRC+, .500 OBP, .100 homers per PA, and .400 hits per PA.

The prediction was, “Matching the ZiPS projection for 2021 would result in .039 Homers per PA, the third highest on the team. He could step into the spotlight as a power hitter.” His .100 homers per PA was more than double the projection and he definitely stepped into the spotlight.

Ketel Marte led the team’s batters with at least 50 PAs with 145 OPS+, .321 BA, .383 OBP, and .529 SLG. His 2.4 fWAR offense was the highest on the team.

FanGraphs’ depth chart projected Ketel Marte to lead the team in doubles and triples, and hits per plate appearance. Those three stats did not happen. Although his .927 OPS and 145 OPS+ and .297 hits per PA led the players with more than 50 PAs, Seth Beer bested Ketel Marte.

The Statcast Swing-Take leaderboard provided a unique insight. That measure adds the outcomes of every pitch in each of the 4 zones (heart, shadow, chase, or waste). Interestingly, Ketel Marte led the team in the heart zone (11 runs) and shadow zone (negative 3). Josh Rojas (19 runs) led in the chase zone. David Peralta (11 runs) led in the waste zone.

As predicted Daulton Varsho contended for the best OPS. The leaders were Marte and Beer. Although the leader in intentional walks per PA (minimum of 100 PAs) was not predicted, in that stat Daulton Varsho led the team with .010 IBB/PA. Honorable mention to Geraldo Perdomo who was intentionally walked in his fourth PA in the Majors.

Eduardo Escobar led the team with 22 Homers and 65 RBIs, even before adding the additional 6 homers and 18 RBIs with the Brewers. However, his 220 assists (2 team total) fell short of Nick Ahmed’s 302 assists.

David Peralta led the team with 8 triples. His career 44 triples ranks third in Dbacks hitters (Royce Clayton was not ranked because he was a Diamondback for only one season). The two ahead of him are Luis Gonzalez with 68 triples and Tony Womack with 59 triples. He failed to lead the team in hits per PA or BABIP.

Merrill Kelly recovered very well from thoracic outlet surgery to lead the team with most innings as a starter (147 innings pitched through 19 September) and 2.4 fWAR. Because of his excellent control, he was projected to lead the team in lowest BB% as a starter, but his 5.7 % BB was second lowest. Lowest was Riley Smith with 5.2% BB as a starter.

Zac Gallen was the only Diamondback projected to have an ERA under 4. Although his actual ERA was 4.53, his expected ERA (xERA) was 3.83. He led the team with 4.00 xFIP, 26.3 %K, and .299 xwOBA.

Madison Bumgarner and Luke Weaver were projected to improve their ERAs. Bumgarner improved his ERA from 6.48 to 4.56 and Luke Weaver improved his ERA from 6.58 to 4.38. They tied for the highest wOBA with .311 through 19 September. Although games scores showed Bumgarner’s starts were inconsistent, his leading wOBA shows that overall he pitched well.

Some stat leaders were unexpected.

Josh Rojas was not projected to lead in any statistics. He led the team with 31 doubles and 55 walks. His 4.0 BsR was the highest on the team. His 173 assists was the third highest.

Pavin Smith was not projected to lead in any statistics. He led the team with 3.9% barrels per PA. He and David Peralta led the team with 43% hard hits. Pavin Smith’s 513 PAs was the highest on the team (that was a close race that could change before the end of the season).

Tyler Gilbert was a gem acquired in December’s rule-5 draft. His 3.47 ERA in 6 games started led the team. His 54.7 average game score led the team.

After the Angels released him, Noe Ramirez was signed as a free agent. His .237 wOBA against, and .186 BABIP as a reliever led the team.

Joe Mantiply’s 3.02 FIP, 4.12 xFIP, .25 HR/9 as a reliever led the team. His 49 games were most games in relief through 19 September.

Caleb Smith’s 25.7 K% as a reliever led the team. This season he started 13 games and had 26 games as a reliever through 19 September.

Riley Smith’s 4.8 BB% as a reliever led the team. Whether he pitched as a starter, or as a reliever, his BB% led the team.

Tyler Clippard’s 2.79 ERA as a reliever led the team. A shoulder capsule strain and minor knee surgery pushed his first relief appearance to 21 July.

Through 21 September, the Diamondbacks’ runs scored per game (RS/G) was 4.18. It was lower than last season’s 4.48 RS/G, lower than FanGraphs’ depth chart projection of 4.65 RS/G, and lower than my projection of 4.98 RS/G. This stat was very much worse than predicted.

Through 21 September, the Diamondbacks’ runs allowed per game (RA/G) was 5.59. It was higher than last season’s 4.91 RA/G, higher than FanGraphs’ depth chart projection of 5.10 RA/G, and higher than my projection of 4.00 RA/G. This stat was very much worse than predicted.

Let’s look at RA per 9 innings to see whether the starters or relievers were better. The Starters had a better RA per 9 innings (5.45 vs. 6.15). Nevertheless, both starters and relievers have room for improvement.

Summary. Some of the statistic leaders were expected in the preseason. Some of the statistics leaders were young new faces, which is a positive takeaway for next season. The big misses in runs-scored and runs-allowed reflected a team whose win-loss record was contending for the worst in the Majors. My view is that the Diamondbacks are young and their stats will improve next season.