May 30, 2024; Atlanta, Georgia, USA; A detailed view of a Washington Nationals hat and glove on the bench against the Atlanta Braves in the ninth inning at Truist Park. Mandatory Credit: Brett Davis-Imagn Images Brett Davis-Imagn Images

Nationals' 18-Year-Old Blows 101 MPH Heater by Cardinals' Top Prospect JJ Wetherholt

Originally posted on Minor League Baseball on SI
By Justin Binkowski | Last updated Mar 19, 2026 9:46 PM ET

The St. Louis Cardinals' top prospect, infielder JJ Wetherholt, has been a must-watch player in spring training this year. But one of the Washington Nationals' young pitching prospects put his own name on the map after throwing a triple-digit heater by the highly touted Wetherholt.

Miguel Sime Jr., Washington's No. 16 prospect for 2026 on MLB Pipeline, put his high-octane fastball on display in the Nationals' 9-8 loss to the Cardinals in Thursday's Spring Breakout game between top prospects from both teams. The 18-year-old threw one inning and gave up one hit, one unearned run, and one walk, while striking out two, including Wetherholt on a 101 mph heater. In fact, the young righty hit as high as 101.9 mph on the radar gun and threw nine pitches at least 100 mph in this outing.

Sime was the Nationals' fourth-round draft pick in 2025 out of high school. The 18-year-old will now enter his first full minor league season with possibly even more Washington fans keeping a close eye on him after showcasing his impressive velocity. And he wasn't the only prospect who made some noise in this Spring Breakout game.

Other Nationals, Cardinals prospects who stood out in Spring Breakout game

Even though Wetherholt struck out against Sime, the Cardinals' top prospect still went 2-for-3 with two runs scored in Thursday's game. The 23-year-old has been trying to earn the nod as St. Louis' Opening Day second baseman all spring, and this showing could have helped his case.

Outfielder Joshua Báez, the Cardinals' No. 4 prospect, contributed by launching a 412-foot two-run homer with an exit velocity of 112.7 mph. On the other hand, St. Louis' No. 2 prospect, lefty pitcher Liam Doyle, didn't have his best outing on the mound. The 2025 fifth-overall draft pick threw one inning and recorded three strikeouts, but he also gave up four runs on two hits and four walks.

For the Nationals, top prospect and 2025 first-overall draft pick Eli Willits went 0-for-1 with two walks, two runs scored, and a stolen base. Washington's No. 5 prospect, Gavin Fien, had a monster game, going 3-for-4 with five RBIs.

Regardless of the outcome, though, this Spring Breakout game offered Nationals and Cardinals fans a brief glimpse at some of the promising prospects who could be a big part of the futures of both franchises.

This article first appeared on Minor League Baseball on SI and was syndicated with permission.

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