Jose Calderon says he was in contact with the Pistons over the first four days of last summer’s free-agency period. But with no offer on the table from the Pistons, the veteran point guard said he had to take a four-year deal from Dallas in July. He suspects they were waiting on forward Josh Smith, who agreed to terms with the Pistons just hours after Calderon agreed to terms with the Mavericks. “They were in contact with me, but I think they were waiting for Josh Smith, so I was just waiting and waiting, and Dallas came with a great offer ... I couldn’t say no to that,” Calderon said Sunday before the Mavs faced the Pistons. Calderon played only 28 games for the Pistons after his expiring contract was acquired from the Raptors in a three-team deal that sent longtime Piston Tayshaun Prince to the Memphis Grizzlies. “I thought they would have came at me with an offer, but at the end of the day, free agency, how it works, you wait and wait and wait until the offer is there,” Calderon said. “It was never there for me to say just yes or no to make a decision.”