At the conclusion of the Czech Extraliga season and prior to the start of the playoffs for HC Kometa, Nečas was loaned to SK Horácká Slavia Třebíč of the 1st Czech Republic Hockey League, the second level of Czech hockey, for their playoff series, playing in their final game. Nečas appeared in 41 games for Brno during the 2016–17 season, recording 15 points. During the playoffs he scored another 4 goals in 10 games, second best on the team, and helped Brno reach the final. However he was unable to play in the final as he was instead sent to the 2017 IIHF World U18 Championships; Brno ultimately won the championship.