Yoan Moncada made his major league debut as a defensive replacement Friday night and is expected to start Saturday .
Yoan Moncada is the No. 5 prospect in ESPN Insider Keith Law 's midseason top 50 .
Yoan Moncada , the No. 5 prospect in ESPN Insider Keith Law 's midseason top 50 , made his major league debut as a defensive replacement Friday night and is expected to start Saturday .