Things like chest flys, DB raises, and cable crossovers are not very effective at maintaining upper body strength but I would still do them anyway. It helps keep the habit of getting in the gym and moving some weight around. I wouldn't count your self out of that goal yet. Wait to see if it is a significant tear or if it's just normal age related changes and you're just dealing with a standard tendinopathy. These are a pain in the ass and take a long time to go away but they don't need surgery, just training management.