This was mentioned by Manning and Underwood last night during the STO broadcast, it is the first I've heard of it (or at least paid attention to it). Good to see that teams don't have to worry about juggling the roster around for day-night doubleheaders anymore. This will come in handy on Monday when we make the call down to Columbus (looks like Monday will be McAllister's turn in the rotation, btw).
The details from ESPN's CBA recap:
• Teams are going to be allowed to expand to a 26-man roster for day-night doubleheaders -- assuming those doubleheaders are scheduled with at least 48 hours' notice. That's a recommendation of Bud Selig's special committee for on-field matters.