[drcy]

The Sporting News is his rookie card. Rookie card means his first trading card as a Major League Player (Federal League or other MLB-level team will count). Can have multiple rookie cards if multiple MLB trading cards came out in the same year. Can't be his rookie card if it's a minor league, college or other non MLB card.

Which one is his best or most desirable or most valuable or rarest or sometimes even first is another question.

P.s., rarity is strictly a measure of the number of cards, while scarcity is a measure of supply versus demand. Market value is as good a representation of scarcity as any. Whether or not you think the T206 Honus Wagner is rare, the $$ value indicates the card is very, very scarce (demand far exceed supply).