Williams was selected as the eighth overall pick by the Phoenix Mercury in the 2016 WNBA draft. She was surprised by the selection since she didn't have many pre draft discussions with the Mercury. Williams has identified Diana Taurasi as a player who “I look up to and who I compare my mentality to”, and now she will be playing on the same team as Taurasi. After appearing in a handful of games for the Mercury, Williams was traded to the Connecticut Sun on June 26, 2016.