This years list includes 26 names so far. The Mariners are highly likely to add more names with the addition of veterans who sign a minor league contract. If you are unaware of what a “non-roster invitee” is, it is just a player who is not on the 40 man roster who will participate in big league camp, as opposed to minor league camp which begins later in the spring.
The biggest name to enter Spring Training as an NRI is obviously Ichiro Suzuki. The Mariners have been quite clear that they plan on having Ichiro on their 28-man roster (special rule for international travel) when the team officially kicks off the regular season in Japan.