Butto is expected to start for the Mets on Wednesday at Washington, Anthony DiComo of MLB.com reports.
Butto was called up last week to work in relief, but he'll be pressed into starting duties after Carlos Carrasco suffered a season-ending finger fracture. Butto, 25, owns a career 6.75 ERA, 1.98 WHIP and 15:16 K:BB in 18.2 major-league innings.