Charlie Villanueva was cut from the Dominican Republic national team for being overweight.
"Charlie was not in good form when we saw him," Calipari told Deportes en la Z. "He was overweight, and unfortunately, we could not slow down the entire team and it was a decision taken collectively. Last year, Charlie behaved really well with us and his only problem was his weight."
Villanueva, 27, has two years, $16.6 million remaining on his contract with the Pistons.
"An NBA player like him deserves respect and for respect, we have taken this decision," Calipari said. "I enjoyed coaching him a lot. He is a great player."