At the trade deadline, the Royals infused their roster with numerous players, among them outfielder Mike Yastrzemski, pitchers Bailey Falter and Ryan Bergert, and the man, the myth, the legend—Adam Frazier.

Some of those players have performed better as Royals than others in this short time. For example, Young Yaz has posted 0.4 bWAR in only 40 plate appearances. Bergert’s earned 0.3 bWAR in just two starts. Falter, meanwhile, mainly due to his first appearance against the Red Sox, has posted 0.4 wins below replacement.

Around the deadline, I wondered who had the best debut season for the Royals. I went digging into both baseball-reference (bWAR) and FanGraphs (fWAR), though the following list isn’t based entirely on the average of the two. I went through every season from 1970 to 2025 (

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