Jason Jennings and Joshua Báez rank as greatest MLB debuts

Báez had five RBIs in his first three plate appearances.

Wire Report IntelligenceUpdated Aug 191 min read

Greg's greatest MLB debuts of all time: 1. Jason Jennings 2. Joshua Báez 3. Juan Marichal 4. J.P. Arencibia 5. Karl Spo Via @MLBNetwork on X

What happened: Jason Jennings recorded the greatest MLB debut of all time. Joshua Báez and Chase DeLauter rank second and sixth, respectively, in historical standing.

Why it matters: Báez vaulted to the runner-up position after launching a 449-foot home run on his very first big-league swing. He was greeted by more than 30 family members following the performance.

By the numbers: Báez amassed 1,199 feet of home runs across his initial contest.

What to watch: Both players continue their rookie campaigns through the remainder of the 2026 season.

Sources

@MLBNetwork 2026-08-19T00:03:53.479215+00:00

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