Sam Jethroe is the oldest player to have won the award, at age 32,[3] 33 days older than 2000 winner Kazuhiro Sasaki (also 32).

[1] This guideline was later amended to 90 at-bats, 45 innings pitched, or 45 days on a Major League roster before September 1 of the previous year.

[1] The current standard of 130 at-bats, 50 innings pitched, or 45 days on the active roster of a Major League club (excluding time in military service or on the injury list) before September 1 was adopted in 1971.

Others, however, believe it should make no difference since the first recipient and the award's namesake played for the Negro leagues before his MLB career and thus could also not be considered a "true rookie".

Jim Souhan of the Minneapolis Star Tribune said he did not see Matsui as a rookie in 2003 because "it would be an insult to the Japanese league to pretend that experience didn't count.