Giants' Mendez closes out Arizona Fall League slate with a gem

MESA, Ariz. – The 2026 season didn’t go the way the Giants envisioned, but the club’s climb to the No. 5 spot on MLB Pipeline’s in-season farm system rankings marked one of the most precipitous rises for any organization in a decade, a sign of the talent that’s on the way.

A huge part of that jump was the fact that San Francisco added a bevy of high-octane arms to its system in July and August via the Draft and prospect capital acquired from multiple trades. The only one of those arms pitching stateside in game action into mid-November is right-hander Miguel Mendez (acquired in the Robbie Ray deal with the Padres), who capped off his year with four no-hit frames and six strikeouts for the Scottsdale Scorpions in Arizona Fall League playoff action on Thursday afternoon.

The only two baserunners to reach against the Giants’ No. 16 prospect came in the form of free passes as he completely overwhelmed a Glendale lineup that managed to put just one ball in play beyond the infield. It was far and away his best outing on the premier prospect circuit after having compiled a 4.91 ERA across six regular-season starts, where he struck out 22 batters in 14 2/3 frames and ran a 1.70 WHIP with 11 walks in that span.

Mendez entered the outing having maxed out during the fall at 98.6 mph – he exceeded that mark seven times Thursday, reaching 99.6 and averaging 98 on the 35 four-seamers that he threw across his 55-pitch outing. His velocity held throughout the appearance, averaging 98.1 mph in the first and 97.7 in the fourth, while five of his six punchouts came against the heater, four of which were swinging.

But his nastiest punchout of the day came on his slider against Tate Southisene (ATL No. 3/MLB No. 58) in the first. Mendez threw his slide piece 86 times in the AFL and batters put it in play just four times – all for outs.

“I’m really focusing on it during my throwing program,” Mendez said of his slider to MLB.com’s Sam Dykstra last month, “trying to use it a little bit more during those times to get it really honed in.”

Another added component of Mendez’s AFL stint was to develop consistency with his changeup, currently a distant third pitch in his arsenal. He threw it just seven times Thursday (all to left-handed batters) and averaged 88.6 mph, still managing to get 9-10 mph of separation off his heater. Continuing to hone his secondary offerings to neutralize opposite-side batters is paramount, even after he ran reverse splits (.241 AVG vs. LHB, .300 AVG vs. RHB) in 2026.

Mendez was limited to 49 2/3 innings this season after missing six weeks due to shoulder and neck issues, returning to action shortly before being dealt in early August. Despite becoming a breakout success story with San Diego in 2025, he’s yet to throw more than 95 frames in a single year and has averaged 5.1 BB/9 throughout his six Minor League seasons (although his 10.7 percent walk rate this year was a career best).

Hurlers with a dynamic fastball/slider combination with upper Minors experience – especially those who are currently on a 40-man roster – often find themselves in the conversation for a big league role. While Mendez has exclusively started for the majority of the past four seasons, he’ll turn 25 by the start of the 2027 campaign, which could expedite his track to Oracle Park.

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The Giants have utilized the starter-to-relief blueprint before. Randy Rodríguez made 13 starts for High-A Eugene in 2022 before transitioning back to the bullpen where he has since pared down his arsenal and blossomed into an All-Star closer (and was also briefly Mendez’s teammate in the AFL before being shut down with right elbow pain) and Carson Seymour developed as a starter ahead of settling into a bullpen niche in his own right.

Ultimately, the bullpen will be a point of focus for president of baseball operations Buster Posey and his group this offseason as they look for a way to improve upon a relief corps that logged the fewest strikeouts (500) in the National League and the lowest K/9 rate (7.55) in the Majors during the 2026 season.