The MLBPA backed out of a deal to expand active rosters from 25 to 26 players for most of the season, but commissioner Rob Manfred said there were "serious reservations" on both sides.
The recent spate of high-profile domestic violence cases involving Ray Rice and other NFL players prompted Major League Baseball and the players' union to open talks about the way that sport should deal with such episodes.
Although Major League Baseball and the players' union continue to discuss possible changes or clarifications to the new home-plate collision rules, union chief Tony Clark told ESPN.com that accomplishing that in-season would be "tough."
