Yep, DaBones had a CL tear. He was non weight bearing on it for the most part, but occasionally would balance himself on his toe.
No surgery for him, no drugs. He was much younger when he did it, but he still was the same quiet guy he is today. I just didn't let him run, not that he would have if given the choice. He was about 3 months until he healed. No further occurrence and it does not bother him today.
CL tear is apparently not a common injury for a greyhound, but it does happen now and again ( according to my vet).
Go luck with your boy!