you have to consider the ramifications of bringing in a replacement. in the scenario that you are outlining, braun would be placed on the voluntary retired list. he could not be replaced by a player sent out on optional assignment, because that player would not have met the requisite 10 days (position player) or 15 days (pitcher) on optional assignment. even if a player is placed on optional assignment early in spring training, the 10 or 15-day clock doesn't start ticking until major league opening day. thus, the replacement for braun would have to be a player from outside of the organization, or a player on a minor league contract. if it was a player on a minor league contract in major league camp with more than six years of service who finished the previous season on a club's 40-man roster or 60-day injured list, that minor league player would need a special retention clause added to his contract guaranteeing that his contract would be purchased on the fifth day of the season--not on opening day. the replacement could also be a player placed on the injured list in spring training, who conveniently is able to be activated the day braun goes on the voluntary retired list. but, you can't time injuries or illnesses, so that's not a viable plan. to that point, if the brewers happened to have an exhibition game or two at american family field prior to opening day (which is not uncommon), they absolutely could have braun as a non-roster player in the starting lineup--and could employ the designated hitter if agreed upon by the opposing club(s) if the dh is not in place for the 2021 season.