San Francisco recalled McDonald from Triple-A Sacramento on Saturday.
McDonald's call-up is the result of Logan Webb (knee) landing on the injured list. It thus seems likely that McDonald will slide into Webb's spot in the rotation, and the former could make his next start Monday in Los Angeles against the Dodgers. McDonald impressed in his only outing with the Giants so this season, allowing one run on two hits and no walks while striking out eight batters over seven innings in a win over the Padres last Monday.