I’d say it seems to be as common as leg/hanstring/quad injuries. Just that oblique injuries are more common in baseball where you’re taking huge swings. We seem to have a lot of guys that take wild swings like Springer, Bo, Vlad, Teo, Lourdes….
I believe Kevin Pillar injured his oblique sneezing in his rookie year.
Its a common injury and im not sure there’s much in the way of prevention