Irving will have surgery in the next week and faces a race against time to be back at 100 per cent in time for the start of the 2015/16 season.
The 23-year-old suffered a knee injury earlier in the post-season and aggravated it in the 108-100 defeat by the Warriors in Game One of the final on Thursday.
Initial tests on Irving’s knee, taken by Cavaliers medical staff, did not show the fracture.
Team-mate LeBron James, who scored 44 points in their most recent defeat, hopes the rest of the Cavaliers will rally round in Irving’s absence but knows much of the scoring burden is going to be on his shoulders.
“Well, there are a few things that you would love to have going late in the season,” James said.
“That’s being healthy, having a great rhythm, and then you need a little luck as well. We’ve had a great rhythm. We haven’t had much luck, and we haven’t been healthy. But I haven’t gotten discouraged.
“I understand the moment that I’m in, and I’m not too much worried about the game. I’m worried about the moment. I’m happy with the moment.
“I’m excited to be in this moment once again, and I’m going to stay strong for my team, no matter who is or is not in the line-up.”