The 25-year-old, who suffered an ankle injury in January which ruled him out for the remainder of the season, has been linked with a move away from St Mary's.
Chelsea, Manchester City, Arsenal and Liverpool have all been reported to be interested in the Dutch international.
"He has a long contract and the directors want to keep him," Puel said.
"He has authority, the leadership of the team, he is a fantastic player.
"It's important for us, of course, to wait until the beginning of the season to see him on the pitch with Southampton."
Van Dijk joined the Saints from Celtic for £13m in 2013 and has made 55 appearances, scoring four times.
Southampton boss Claude Puel says the club do not want to sell captain Virgil van Dijk.