Roki Sasaki faces a crucial test this Saturday as he takes the mound against the St. Louis Cardinals, with his spot in the Los Angeles Dodgers' starting rotation hanging in the balance. The 24-year-old Japanese phenom has stumbled out of the gate in 2026, posting a disappointing 6.35 ERA and a 1-2 record that has labeled him the team's biggest letdown of the season, according to ESPN's Jeff Passan.

So what's gone wrong for the young right-hander? According to Dodgers Nation's Doug McKain, the answer lies in Sasaki's fastball—his most frequently thrown pitch. While Sasaki can still light up the radar gun at an average of 97.1 mph (placing him in the top 12% of MLB pitchers per Baseball Savant), his command has been erratic, leading to disastrous results. His pitching run value sits at -10, worse than 98% of pitchers, while his fastball run value is -8, worse than 97% of the league. Opponents are teeing off, with his expected ERA at 6.05 (bottom 11%) and expected batting average at .275 (bottom 18%). As McKain put it, Sasaki's fastball "has been absolutely tattooed this year."

The silver lining? Sasaki is still just 24 years old, with plenty of time to refine his game. McKain believes he's "one fastball command away from being a really good big league starter," noting that his heater looks nothing like the dominant pitch he featured in Nippon Professional Baseball. With Sasaki throwing his fastball 41.5% of the time, fixing that command could transform a large chunk of his arsenal into a weapon instead of a liability.

Time is of the essence, though. Blake Snell is nearing his return to the Dodgers' roster, which could push Sasaki out of the rotation if he doesn't show improvement. The question now is whether he can rediscover the form that made him a star in Japan before the competition for starting spots becomes even fiercer. Do you believe Roki Sasaki has what it takes to turn things around?