Each year as spring training approaches, most big league clubs will have a crop of non-roster invitees that join the guys on the 40-man roster at big league camp. Typically, that group is made up of some combination of top organizational prospects who have had a year or two of minor league experience, and major league and/or upper-minors veterans who are trying to crack an opening day roster one last time.
Last year, none of the Mariners’ 21 NRI’s played their way onto the 25-man for the Mariners when they opened their season in Houston, but eight of them did end up seeing time in the big leagues at some point last season.