The Best Individual Pitching Performances from Each Starter in 2023

Let's take a look at the most impressive single-game outings from each player on the starting rotation.

Texas Rangers v Seattle Mariners
Texas Rangers v Seattle Mariners / Steph Chambers/GettyImages
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It's no secret that the Mariners have some of the best starting pitchers in baseball today. However, when evaluating pitchers over 20-30 starts, it can be easy to lose track of what they're capable of when they're at their very best. Using a metric called Game Score, let's see how just good our guys really are.

Here is MLB's definition for the stat:

"Game Score measures a pitcher's performance in any given game started. Introduced by Bill James in the 1980s and updated by fellow sabermetrician Tom Tango in 2014, Game Score is presented as a figure between 0-100 -- except for extreme outliers -- and usually falls between 40-70.

A Game Score of 50 is considered "average," while a Game Score of 40 is deemed to be "replacement level." Game Scores in the 80s and 90s are widely regarded as impressive, and scores of at least 100 are exceptionally rare. Using Tango's formula, which is the version displayed on MLB.com, only nine of the 4,858 games started in 2015 resulted in Game Scores of 100-plus."

Luis Castillo - April 16th vs. COL (7.0 IP, 2 H, 0 ER, 0 BB, 9 K)

Game Score: 82

In a dazzling show against the Rockies in mid-April, Castillo was nearly unhittable, giving up just two singles on the way to striking out nine batters and giving up no free trips to first base. While the Rockies didn't field the most threatening offense in the league in 2023, they still had a league-average OPS against right-handed pitchers. In addition to his nine strikeouts, Castillo earned 19 swings and misses and topped out at 97.9 mph on his four-seam fastball, a stark difference from his changeup which sat around the 87 mph mark.

While known for his changeup in his days with the Cincinnati Reds, Castillo has definitely evolved his game to rely more heavily on his four-seam and sinker combination. In fact, his changeup was his least used pitch in 2023 and the worst pitch by run value (-9). He's decreased his total usage of the off-speed pitch over the past few years but with a similar movement profile and arm-side run, his sinker is just as good and will only get better. Meanwhile, his four-seam fastball had an opposing BA of just .165, so it's safe to say he won't be "changing that up" anytime soon.

Interestingly enough, the Mariners won this game 1-0 with the team barely enough run support to escape with the win, seemingly a team tradition for the team's great pitchers.