If ASA is getting 28 70 seaters that will be nearly 600 training events. Each airplane should be staffed with about 5.5 crews, or 11 pilots. That would mean 308 new hires, plus another 200, or so for attrition.
But things could change on a dime. 40 of the 50 seat airplanes are being left on Delta's books so that they will be wasy to dump if (when) Delta has a serious retrenchment.