Once you look at his injury history comprehensively.
There is no reason to assume that he will be back by May.
Sano seems to have his own special diminished healing capabilities and I'm not stating that to be a jerk toward him. There is just very little else that can be assumed when you review his entire injury history.
Tommy John Surgery that knocked out an entire year... A foul ball that advanced from shin soreness to a titanium golf club in his left leg. A grade one hamstring strain that took a month. A bad slide that led to a clean MRI but a puzzling knee that knocked him out for the rest of the season. And now a laceration has turned into immobilization and more significant time on the DL as a result. I'll be shocked if he is back by May and if he comes back in May... I'll be shocked if the laceration doesn't come back after two games and we end up reading Lavelle E. Neal explaining that he will be under going a skin transplant.
If you squirt him with a squirt gun... it'll turn into Jennifer Beals in Flashdance.