 The Celtics closed out the exhibition play in the Summer League in Las Vegas with a 2-3 record. Meanwhile, the Celtics are doing everything they can to keep their championship roster intact. ESPN reported yesterday that Sam Hauser agreed to a four-year, $45 million contract extension. The 26-year-old shot more than 42% from the three-point line last year. He was slated to become a free agent after this upcoming season.