http://www.vgchartz.com/preorders/42799/USA/
They have MLB ps4 at almost 300k pre orders with 3 weeks of numbers left. That would suggest the title is lining up a 500k retail opening in the US only.
Which in turn would suggest including digital and all other markets they would ship close to a million week 1.
Incase you don't already know Vgchartz has the other titles selling only about 1m life.