Since three days is more than enough time for a father to spend with his newborn son, Munenori Kawasaki has been re-activated from the paternity list and will be re-joining his team in New York tomorrow as the Blue Jays face the New York Yankees. To make room for him, reliever Thad Weber has been optioned to the AAA Buffalo Bisons--formally, at least.
Because the Blue Jays and the Yankees play a doubleheader tomorrow, both teams are allowed to expand their active roster from 25 to 26 players. Thad Weber has already been tapped to be recalled tomorrow, so he is most likely with the team in New York City rather than Buffalo.
The player being recalled as the "26th man" does not have to wait the customary 10-day period after being optioned to re-join the major league club; however, if that player has not accrued 10 days on his optional assignment directly preceding the recall, he must be the one optioned after the doubleheaders. That means, unless someone will be placed on the disabled list, Thad Weber will be the one who will be optioned after the games tomorrow. That is good news for Buffalo Bisons fans, as they look for some help in their final push towards the postseason.
This roster expansion rule came about in 2012 with the latest Collective Bargaining Agreement between Major League Baseball and the Players' Association. The rule allows clubs to carry up to 26 players for day-night doubleheaders (one where the stadium in cleared between games and two admissions are charged) which are scheduled at least 48-hours in advance. The roster expansion helps clubs manage their bullpens better on days when two games are played.
The Yankees have not announced who they will be recalling for tomorrow.