In the realm of fantasy baseball, the fate of three struggling starters hangs in the balance. As we delve into the intricacies of their performances, it becomes evident that a deeper analysis is required to determine whether these pitchers are mere victims of bad luck or if there's a glimmer of hope for improvement. Let's take a closer look at Luis Castillo, Jack Flaherty, and Tanner Bibee, and unravel the mysteries behind their recent struggles.
Luis Castillo: A Tale of Unlucky Breaks
Luis Castillo, once a stalwart of the Mariners' rotation, has found himself in a predicament in 2026. With an ERA of 6.57, WHIP of 1.62, and K-BB% of 13%, Castillo's performance has been a stark contrast to his previous seasons. The numbers tell a story of bad luck, as evidenced by a .364 BABIP and 59% strand rate. However, a closer examination reveals a more nuanced picture.
Castillo's four-seamer, once a potent weapon, has been met with a .399 wOBA by right-handed hitters, a significant departure from its previous performance. The pitch's vertical break has remained consistent, but its effectiveness has waned. Interestingly, Castillo has been throwing the four-seamer more towards the outer third of the plate to righties this year, a strategic adjustment that may have contributed to the decline in results. Despite this, Castillo's Location+ on the four-seamer remains impressive, at 117, indicating that he is still locating the pitch well.
The slider, Castillo's other primary pitch, has also undergone a transformation. Historically, it has been a source of weak contact, but in 2026, right-handed hitters have been hitting it harder, as evidenced by a .355 wOBA. The heatmaps reveal that Castillo has been throwing the slider slightly more over the plate in the lower parts of the zone, a change that has likely contributed to the increase in contact. However, the good news is that Castillo's slider Location+ is still strong, at 113, suggesting that he can still locate the pitch effectively.
In my opinion, Castillo's track record and the Mariners' organizational trust make him a hold in most fantasy rosters. While the expected ERA and underlying metrics don't support better outcomes, the potential for improvement in his slider locations and command gives me hope. Castillo's high-end command and above-average stuff make him a valuable asset, and I believe he can turn things around as the season progresses.
Jack Flaherty: A Sliding Act
Jack Flaherty, once a force to be reckoned with, has found himself in a slump in 2026. With an xFIP of 5.19, xERA of 4.77, and SIERA of 4.75, Flaherty's performance has been a disappointment. The numbers tell a story of a decline in strikeout skills, particularly with his breaking pitches.
Flaherty's knuckle curve, once a whiff machine, has seen its swinging-strike rate dip to 15.7% in 2026. The movement profile and stuff grades of both the knuckle curve and slider have remained relatively unchanged, yet their effectiveness has waned. Opposing hitters have been chasing less often, and the increased contact on these pitches has been concerning. Left-handed hitters, in particular, have been feasting on Flaherty's pitches, with his four-seam, slider, and knuckle curve all suffering.
The visual below shows the concerning decline in Flaherty’s strikeout skills, which we’ll continue to discuss.
In my opinion, Flaherty's current struggles are a result of a combination of factors, including a decline in pitch movement and stuff grades. The make-or-break week for fantasy managers was likely the one where Flaherty allowed six hits, three earned runs, three walks, and two strikeouts in 3.2 innings. Unless the slider and knuckle curve whiffs bounce back, it's best to stay away from Flaherty. His current performance doesn't align with his skills, movement profiles, and stuff grades, making it a risky proposition to hold onto him.
Tanner Bibee: A Rising Star in the Making
Tanner Bibee, a right-handed pitcher, has been on a rollercoaster in 2026. Before a quality outing against the Twins, Bibee's results had been brutal, with a 4.58 ERA, 1.47 WHIP, and a 12% swinging-strike rate. However, on Saturday, Bibee elicited 20 whiffs in a game, a feat he hadn't achieved since June 2024. This was a significant improvement, and it raises hopes for his future performance.
Bibee's changeup, a pitch with an 18.5% swinging-strike rate, has been a key factor in his success. The pitch allows weak contact, particularly against left-handed hitters, with a .154 wOBA. Interestingly, Bibee's changeup Stuff+ ranks third among right-handed pitchers, behind Michael Wacha and Cristopher Sánchez. This suggests that Bibee's changeup is not just a whiff machine but also a pitch that can be located effectively.
Bibee's cutter, another above-average pitch, has also been effective, with a 19.4% swinging-strike rate. The pitch's horizontal movement profile theoretically should help with weak contact, and its Stuff+ grade is decent, at 102. Bibee's arm angle and horizontal release point adjustments have led to over one inch more glove- or arm-side movement across his entire arsenal, a positive development that could bode well for his future performance.
In my opinion, Bibee is a rising star in the making. His two pitches with an above-average swinging-strike rate, stuff, and pitch mix adjustment support potential improvements in his results moving forward. While his WHIP may be bumpy, the ERA estimators suggest that better results are coming soon. Bibee's changeup and cutter, combined with his new arm angle and horizontal release point, make him a pitcher to watch in the coming seasons.
