I had a similiar experience Charlie, some years back one of my athletes had been going really well, ran pbs for 100/200 then suffered an achilles tendon problem. She rehab’d for a few weeks by drilling then eventualy striding and sprinting on grass. She had entered a championship at 400m (her main event) so we did about 10 days or so of track for speed and recovery on grass. She ran a pb for 400m in the championship, so yes I agree it can work. 