Moustakas was diagnosed with a bruised right forearm following his departure from Monday's game against the Red Sox, Rustin Dodd of The Athletic Kansas City reports.
Moustakas will receive X-rays on his forearm to determine the severity of the injury. Consider him day-to-day until further notice, although Cheslor Cuthbert would likely spend time at third base if Moustakas has to miss a game or two.