The Cavaliers are down to their third string playmaker. The only problem is identifying who exactly that might be. They faced another playoff team Monday and lost to the Indiana Pacers 111-90 because they were pushed around inside by a much more physical, dominant opponent. Role players for the Pacers had terrific games while the Cavaliers struggled to score. A large reason for that was the absence of Dion Waiters, who left after the first quarter with soreness in his left knee and didn’t return. Waiters said the knee has been bothering him for the past couple of games. It didn’t feel right at the start of the game Monday and apparently grew worse. He mentioned something to trainer Max Benton after the first quarter, and his night was finished. He’ll go for testing today before a decision on his future is made. This is the worst possible stretch in the schedule for the Cavs to lose key players, but it’s reasonable to expect Waiters will miss at least a little time — and the Miami Heat are coming to town carrying that remarkable 23-game winning streak. With Kyrie Irving already out and now Waiters perhaps sidelined, Cavs coach Byron Scott was asked what Plan C is for the offense. “Besides go home tonight, get on my knees and pray?” he said.