With the influx of so many new players this season, whether from the amateur ranks or from other professional leagues, I got curious as to who would qualify as a rookie. Is it merely a matter of being new to the league? Or does a player have to come from an amateur league? Are there any age restrictions?
Good question. My first thought is that a "rookie" is someone playing in her first professional season. But what about players in these "semi-professional" leagues that I hear about? What about players from other countries? I recall that when the Mexican women's league was founded a few years ago, some people argued that it was only a "semi-professional" league. As I recall, the "purists" or misogynists, whichever term applies, argued that players in the Mexican league were not worthy of a Wikipedia article because they weren't professionals.
The NWSL defines a rookie as a player in their first season as a professional. For internationals, I'm not exactly sure which leagues they'd define as professional, but I'd think it'd include some that are technically semi-pro but are the top-tier league in a country. Of course, we've never really had a "test case" since most who've been named Rookie of the Month or Rookie of the Year have come through the US system where it's clear if you're pro or not. EDIT to add: A lot of the internationals coming into the NWSL this year are new only to the NWSL, but are not, by any definition, rookies as they've transferred from European or Chinese clubs.
Several leagues will have a 'Newcomer of the Year' award for those transferring in from other professional leagues.
The NBA has given rookie of the year to Pau Gasol and Luka Doncic, who both played professionally in Europe before joining the NBA. It's entirely possible that the NWSL has different rules and exclude players who have played professionally in other leagues from winning rookie of the year.
They should have. NBA, WNBA and NHL are so much better than other leagues in their sports that everyone new in them should be considered a Rookie. For NWSL or MLS that can not be said, NWSL may possibly be the best league in their sport but if so not with any margin to speak of and MLS can't even claim that.
The NWSL publishes a Rookie Report weekly. Those identified in the report all appear to be players taken in the most recent college draft.