In 2012, Nečas participated in the Quebec International Pee-Wee Hockey Tournament with a youth team from Chomutov.[1] A standout junior player, Nečas led the Czech under-16 league in scoring in 2014–15 with 91 points in 34 games, split between the junior teams of Žďár nad Sázavou and Kometa Brno.[2] His production decreased in 2015–16 due to missing games from injuries and illness, appearing in only 18 games, with nine goals and 21 assists.[3] Nečas made his professional debut with Brno in 2016, joining the senior team in the Czech Extraliga.
At the conclusion of the 2016–17 Czech Extraliga season and prior to the start of the playoffs for Kometa Brno, Nečas was loaned to Horácká Slavia Třebíč of the 1st Czech Republic Hockey League, the second level of Czech ice hockey, for their playoff series, playing in their final game.[4] Nečas appeared in 41 games for Brno during the 2016–17 season, recording 15 points.[5] During the playoffs he scored another four 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 World U18 Championships;[6] Brno ultimately won the championship.[7]
When the NHL Central Scouting Bureau released its mid-term rankings of eligible prospects for the 2017 NHL entry draft, Nečas was listed as the fifth-best international skater.[8] He maintained this position on the final list released after the conclusion of the 2016–17 NHL regular season.[9] Scouts considered him an undersized forward, but smart and someone who has good offensive instincts and a strong skater.[5] Following his selection by the Hurricanes, 12th overall, Nečas was later signed to a three-year, entry-level contract with Carolina on 15 July 2017.[10]
Initially it was expected that Nečas would not join the Hurricanes immediately, and instead was expected to either return to the Czech Republic, or play for the Hurricanes' American Hockey League (AHL) affiliate, the Charlotte Checkers, or the Saginaw Spirit of the Ontario Hockey League (OHL), who selected him in the CHL Import Draft in 2017.[11] His play during Hurricanes' training camp, where he demonstrated his skill, earned him a roster spot. The decision to keep Nečas with the team was aided due both to an injury to veteran Lee Stempniak, and that Nečas could play up to nine regular season games in the NHL before it counted against one year of his contract.[12] Though named to the roster, Nečas was a healthy scratch and only practiced with the team, and his NHL debut came 17 October 2017, in a 5–3 win over the Edmonton Oilers.[13][14] Nečas remained on the Hurricanes roster until 23 October, though did not appear in any more games, when he was returned on loan to continue his development in Brno.[15] Nečas had 17 points in 24 games, leading junior-aged players in scoring, and helped Brno win the Czech Extraliga championship for a second year in a row.[16][17]
Nečas started the 2018–19 season with the Hurricanes in the NHL. On 16 October 2018, he recorded his first NHL goal on a pass from fellow rookie Warren Foegele in a 4–2 loss to the Tampa Bay Lightning.[18] After seven games with the Hurricanes, where he had one goal and one assist, Nečas was assigned to Hurricanes' AHL affiliate, the Charlotte Checkers.[19]
Considered the top prospect in Carolina's system going into the 2019–20 season, Nečas was named to the team for the start of the season. On 3 October 2019, he scored a power play goal in the season-opening 4–3 shootout win against the Montreal Canadiens.[20] On 9 August 2022, Nečas was re-signed to a two-year contract extension until the end of the 2023–24 season.[21] In the first year of the extension, during the 2022–23 season, Nečas led the Hurricanes in points with 71. On 29 July 2024, the Hurricanes re-signed Nečas to a two-year contract.[22]
