Mountcastle went 2-for-5 with a two-run home run and two runs scored in a loss to the Red Sox on Saturday.
Mountcastle hit the first of three homers off Chris Sale with a two-run shot in the first inning. He also singled and came around to score on a double by Anthony Santander. It's a strong start to the season for Mountcastle, who is going to get plenty of RBI chances hitting behind Adley Rutschman to open the year.