Sheffield, Frazier among potential Yankee September call-upsMLB allows rosters to expand starting Saturday9/1/2018, 12:25 AMJul 15, 2018; Washington, DC, USA; USA pitcher Justus Sheffield (4) pitches during the second inning against the World Team during the 2018 All Star Futures Game at Nationals Ballpark. Mandatory Credit: Geoff Burke-USA TODAY Sports / Geoff Burke