J.R. Smith is confident the Knicks have a chance to win what is suddenly a wide-open Eastern Conference, with the splintering of the Big 3 in Miami. “Extremely realistic,” the Knicks shooting guard said on “First Take” on Wednesday morning, when asked how realistic it was that the Knicks could win the East. “I’m confident. I don’t play to lose.” After winning 54 games, the Atlantic Division, and a playoff series two years ago, the Knicks floundered to a 37-45 record and missed the playoffs last season. Smith was one of the culprits in the collapse. He said he would not have been surprised to be dumped by Phil Jackson this summer. “I was playing like a person who didn’t want to be there, not looking as focused as a person who should be,” he said. Before the season, while recovering from knee surgery, he was suspended for five games due to a positive marijuana test. Once he returned to the court, Smith was abysmal for two months, shooting 32.8 percent in November and 36.8 percent in December, far off his career field-goal percentage of 42.5 percent. “I’m not going to make any excuses for myself, but knee surgery is a tough thing to come back from,” he said. “I didn’t expect to be [back to] where I was.” As the season wore on, discord engulfed the team. Smith alluded to a rift between Raymond Felton and Tyson Chandler.