According to a Mavericks source, restricted free agent center Nerlens Noel has ended a summer-long negotiations stalemate by signing a one-year qualifying offer of $4.1 million to return to Dallas for the 2017-18 season.The Mavericks source confirmed an earlier report by ESPN's Chris Hayes. Saturday's news comes less than a week after Noel replaced agent Happy Walters with Rich Paul of Klutch Sports.