Greater Western Sydney (2012–2015) Treloar was recruited by as an under-age selection prior to the
2010 AFL draft and played with the
Dandenong Stingrays and the
Noble Park Football Club during his junior career. In 2011 he played for
GWS Giants in the
NEAFL one year prior to their
AFL entry. He made his AFL debut in round 3,
2012 against at
Blacktown International Sportspark. He was the round nomination for the
Rising Star after the round 18, 120-point loss to , where he amassed 39 disposals. He went on to finish fourth overall in the award after receiving 15 out of a possible 45 votes. Treloar played 20 games during 2013, averaging 24 disposals a match, and finished fifth in the
best-and-fairest count. He was touted by former forward
Dermott Brereton as the next
Mark Ricciuto, saying that he had the potential to "be an absolute elite player in the midfield and be top five in the comp with his ability, with his skill set and with his want and desire for the game." His 2014 season was described as "brilliant" where he averaged 27.6 disposals and 5.5 tackles in 20 matches and finished fourth in the best-and-fairest count. He was recognised as one of the best young players in the league by being selected on the wing in the AFLPA
22under22 team. Treloar had his best season to date during 2015 where he was the runner-up in the best-and-fairest, finishing behind
Heath Shaw, however, his season was filled with speculation that he would leave the Giants to return to his home state of
Victoria. He informed the club in September that he wanted to be traded and nominated Collingwood as his preferred destination.
Collingwood (2016–2020) Treloar officially joined Collingwood on a six-year deal on 21 October 2015. He had an outstanding first season for the club, playing all 22 games, and lead the club for disposals, tackles, clearances, inside 50s and bounces. At the end of the season he won the R.T. Rush Trophy, finishing second in the
Copeland Trophy count, behind skipper
Scott Pendlebury. Treloar followed up with a consistent second season at the club in 2017, playing in 21 games. In 2018, Treloar won the
Anzac Medal, and later played in the losing grand final to West Coast. Treloar's 2019 season saw him win plenty of the football, he finished the season with a total of 789 disposals which saw him lead the entire AFL in the home and away season, as well as finals, he also did lead the league in handballs, tallying 454 for the season. His season was highlighted with 40 disposals and 7 tackles against North Melbourne in Round 15, he averaged 32.9 disposals per game, played 24 games and polled 18 Brownlow Medal Votes. He was awarded the Jock McHale Trophy for finishing fourth in the 2019
Copeland Trophy vote count. As the
2020 AFL season drew to a close, rumours began to circulate that Treloar would seek a move to Queensland, after his partner
Kim Ravaillion signed a one-year deal to play netball with the
Queensland Firebirds and temporarily relocate to Brisbane with the pair's daughter. It emerged that it was in fact Collingwood seeking to move on Treloar and his remaining five-year contract, citing both salary cap concerns and concern for his mental wellbeing due to the distance from his family - though Treloar remained steadfast in his desire to remain in Victoria. Treloar was traded from Collingwood to the
Western Bulldogs on 12 November, in the final minute of trade period. Collingwood received pick 14 and a future 2nd round pick, while the Bulldogs received Treloar and picks 26, 33 and 42.
Western Bulldogs (2021–present) Treloar suffered a syndesmosis injury in Round 10 of the
2021 AFL season, which was announced to keep him out of the side for up to two months. At that stage the Bulldogs had won 9 out of 10 games. He returned to play from Round 21 onwards, which started with 3 consecutive losses to finish the regular season as the Bulldogs fell out of the Top 4 by just 0.5%, thereby losing the "double chance". The Bulldogs regained their form to win all 3 finals including the Preliminary Final demolition of Port Adelaide in Adelaide, which set up the Grand Final match against
Melbourne in
Perth after the bye. In the
2024 AFL season, Treloar played 22 home-and-away games in addition to the Bulldogs' elimination final loss to , throughout which he kicked a career high 16 goals and led the league for average disposals. In recognition of his Career Best form he was awarded with
All-Australian team honours, being placed on the interchange bench. ==Statistics==