Don't think there's much option but to get him match fit by playing him. He'd surely offer more presence. He's not going to get up to speed playing reserves football, in the gym or by playing 10 minutes at the end of lost cause matches. if he's a dud then let's at least find out that he is.
Leonard looked a peripheral figure against those big defenders and in an ideal world goes on loan, though that can't happen clearly given the numbers.