Dating back to 2006, just six players have hit 15 or home runs at Double-A before turning 20 years old. Rainiel Rodriguez became No. 6 on Thursday night, joining a list that includes Giancarlo Stanton, Fernando Tatis Jr., Jackson Chourio, Samuel Basallo and Leo De Vries (MLB’s No. 2 prospect).
That’s it, that’s the list.
The Cardinals’ No. 1 prospect has gotten there on the back of a scorching-hot month of August, which rolled on during Double-A Springfield’s 3-2 win over Arkansas at Dickey-Stephens Park. The homer (his 19th of the year across two levels) marked his fourth straight game plating a run as he’s slashing .407/.446/.746 with 12 of his 24 hits going for extra bases since the calendar flipped. Even in the offense-heavy Texas League, his 44 total bases rank tied for second on the circuit in that span.
Facing left-hander Nico Tellache (Mariners), almost nine years his senior, Rodriguez unleashed an enormous wallop in the third inning, sending a center-cut fastball out to the deepest part of the ballpark in left-center field. As the second-youngest everyday player at Double-A, baseball’s top-ranked catching prospect has yet to face a hurler younger than him in 2026. But that hasn’t slowed him in the slightest. After hitting .311 with a .949 OPS in 28 games at High-A Peoria, he got the bump to Springfield in mid-May and has since hit .309 with a .928 OPS.
There aren’t many categories across the Cardinals farm system in which Rodriguez hasn’t established himself near the top of the pack. He leads the way in hits (119), batting average (.310), on-base percentage (.400), OPS (.934) and wRC+ (138).
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It’s been a meteoric rise through a stocked St. Louis system for Rodriguez, who signed in April 2024 out of the Dominican Republic. His final at-bat Thursday marked the 1,000th plate appearance of his professional career and the slash numbers are largely in line with what you would expect from a teenage phenom: .304/.411/.567.
Using the above list of big leaguers as a rough point of demarcation, Stanton, Tatis, Chourio and Basallo all logged at least 1,211 plate appearances before making their Major League debuts. But it’s also worth noting that none of that quartet approached the numbers at Double-A that Rodriguez, now MLB’s No. 18 prospect, is putting up. Basallo had the highest average at .292, while Stanton led the way with a .906 OPS, both below where Rodriguez ranks in his first taste of the upper Minors.
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The Cardinals have monitored Rodriguez’s workload behind the dish in 2026. He hasn’t caught on three consecutive days all year with reps at first base sprinkled in at a higher frequency, including 21 starts at the cold corner (where he’s yet to make an error) between Peoria and Springfield.
Things can change quickly across the Minors, especially for standout performers. Joshua Báez (STL No. 3/MLB No. 59) posted a four-homer game for Triple-A Memphis on June 16, and well, his Major League debut from last week might go down as the best in history. Exactly one year ago, JJ Wetherholt -- now firmly in the National League Rookie of the Year conversation -- was amidst a hot streak at Triple-A after spending the summer tormenting Texas League hurlers much in the same way Rodriguez has done since arriving.