Garcia, 26, hit .327 with five homers and 20 RBIs in 15 games in April. He's hitting .328 with six homers, 25 RBIs and a .418 on-base percentage for the season. Garcia leads the Southern Leauge in RBIs, on-base percentage, slugging percentage (.672) and OPS (1.089).
The Cubs signed garcia last October. He most recently had played in the Italian Baseball League for UnipolSai Bologna in 2018.
Miller, 23, had a 1.42 ERA in four starts in April. He has a 1.07 ERA in five starts for the season, a mark that ranks third in the Southern League. He has a 0.75 WHIP and has held opponents to a .138 batting average. The Cubs drafted Miller in the fourth round in the amateur draft in 2016.