Moncada made his major league debut Friday night, entering Boston's 16-2 win over Oakland in the seventh inning and getting two at-bats.
Moncada's highly anticipated debut came in a low-pressure situation, with Boston leading by 10 runs. He walked in his first plate appearance, scoring on a Travis Shaw double, then struck out in his other appearance. The plan going forward is to have Moncada start at third base whenever Boston is facing a right-handed starter, which will happen Saturday when the A's throw right-hander Daniel Mengden.