Since Major League Baseball’s expansion era began in 1961, 13 rookies 29 or older have had Fangraphs wins above replacement of 2 or higher.
Of those, only Casey Blake bettered his rookie fWAR and only Blake and Ed Charles finished with career fWARs of 10 or better.
Older rookies are in their prime when they arrive, with little time for growth in their games.
Whether Patrick Wisdom and Frank Schwindel can join the exceptions after age-29 breakthroughs is a prime question for the Cubs in 2022. They are the only active players on the list of 13.