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.