April 3, 2026, could go down as a legendary date in Pirates history.
Not only did the club’s top prospect, Konnor Griffin, make his big league debut and rope an RBI double in his first at-bat, but its No. 2 prospect, Seth Hernandez, officially toed the rubber for the first time as a pro after he was selected in the 2025 Draft with the sixth overall pick -- and he looked every bit the part.
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Hernandez racked up a whopping eight punchouts and surrendered one run over three frames for Single-A Bradenton in its 6-4 win over Dunedin at TD Ballpark. In other words, he recorded all but one of his outs via the strikeout.
Not only that, but MLB’s No. 26 prospect also tallied 18 whiffs on 24 swings, good for a 75 percent whiff rate. That many whiffs at that high of a rate had been reached only one other time since Statcast was installed in Florida State League stadiums in 2021 (former Minnesota prospect Osiris German had 18 whiffs on 23 swings).
If you expand the search to include Triple-A, left-hander Matt Krook had 12 whiffs on 14 swings (85.7%) as a member of Triple-A Scranton/Wilkes-Barre on June 24, 2023. If you include the Major League level (dating back to 2008), Josh Hader had 15 whiffs on 19 swings (78.9%) as a member of the Brewers on May 19, 2018.
Both were dominant outings, but neither as good as Hernandez’s.
Touted out of high school as perhaps the most advanced prep right-hander ever, Hernandez entered 2026 surrounded by hype -- and that was even before the 19-year-old froze fellow Top 100 prospect Max Clark with a 102.4 mph four-seamer at Spring Breakout.
In the California native’s first official start as a pro, his 70-grade fastball was just as electric. Hernandez averaged 97.9 mph and 19 inches of induced vertical break (MLB average is 16 inches) with the offering.
Seven of his eight strikeouts were finished off by either his slider or curveball. One strikeout was secured after a batter pitch timer violation. Hernandez’s pair of offspeed pitches accounted for 12 of the 18 swings-and-misses. The slider in particular -- which registered officially as a cutter because of its high velocity -- produced eight whiffs.
Konnor Griffin coverage:
• Griffin rips RBI double in 1st career plate appearance
• Complete scouting report | What to expect
• Everything to know about Griffin | By the numbers
• How does Griffin stack up to all-time great prospects?
• Griffin's unique connection to Hall of Famer Mazeroski
• Best No. 1 prospects in MLB ranked
• Most anticipated debuts in baseball history
Taking the mound opposite the 6-foot-4 right-hander, was Blue Jays playoff hero Trey Yesavage. The 22-year-old -- ranked as MLB's No. 9 prospect -- fanned three and allowed one run over 2 2/3 frames. The start represented his first rehab outing as he works his way back from a right shoulder impingement.
Hernandez outdueled a big leaguer in his first start as a pro. What could his future outings bring?