I think Mastrobouni is at least as good as Madrigal (probably better)at the plate and can steal bases. I also think the idea of Madrigal being this star fielder is a bit overblown. He was fine. But as we know from one year to another those metrics can change easily. Add to it that Mastrobuoni hits left handed and can play SS and even the outfield, and that is why I like him a little more than Madrigal. Honestly, to me it is splitting hairs between the two of them. Bottom line is, most likely both will make the team. My guess is both Cooper and Peralta are released when all are healthy. .
If only one of them made the team, to me, it would be the guy who hits from the opposite side of the plate that the 26th player hits from. So if Peralta is 26, keep Madrigal. If Cooper is 26th, keep Mastrobouni up. That is how little difference I see in them.