According to Baseball America (sub. req’d), MLB has plans to implement player limits and possibly to expand minor league rosters. Early on, MLB was considering a limit per organization of 150 players assigned to domestic affiliates, i.e., not counting the Dominican Summer League. That would make it impossible for teams to operate two rookie level affiliates. Given the very large numbers of international signings the Pirates have made in recent years, it’s very difficult to see how they’d manage with no short season teams and only one GCL team, apart from releasing a lot of players and keeping other players for 2-4 years in the DSL.
According to BA, MLB is now considering a 180-player limit. That would allow the Pirates to operate two GCL teams. Of course, they could find other alternatives, like having players scrimmaging in an extended spring training environment. By my count, the Pirates currently have about 176 players slated for their domestic affiliates. That includes space for 40-man roster players who’ll get optioned, as well as players from the DSL who’ve been to fall instructionals the last two years. It doesn’t include space for players still to be signed to minor league deals; the Pirates are going to need to add some pitchers, and probably a couple position players, for AAA. It also doesn’t include the likelihood that more players will be moving up from the DSL beyond the ones who’ve already been to fall instructionals. So the Pirates are going to have to make some more cuts.
MLB is also considering expanding the minor league active roster limit. In the past, teams have had 25-man rosters. The parent teams have evaded that limit by having extra players travel with their affiliates, using paper moves to activate and deactivate players, mostly to have rested pitchers available. So expanded rosters won’t really change anything beyond making official what’s already being done.