Barrass underwent a growth spurt and was recruited by his zoned Western Australian Football League (WAFL) club Claremont.

[4] He recorded 18 disposals in Claremont's six-point grand final victory over South Fremantle,[5] and believed he was close to lining up for the senior side before dislocating his finger.

[3] Barrass played for Western Australia in the 2013 AFL Under 18 Championships, where he was mentored by fellow backman and then-West Coast captain Darren Glass.

[4] In January, prior to the 2014 AFL season, Barrass underwent an arthroscopy to repair a torn hip joint, ruling him out of training for three months.

[9] Gavin Bell, West Coast's Head of Development, was impressed with Barrass's performance and noted his marking and ball use as standouts.

[12] In July, coach Adam Simpson said Barrass was ready to play at AFL level, but noted the backline was "pretty settled" and it would be hard for the defender to claim a spot.

[13] After McGovern hurt his left hamstring against Collingwood, Barrass replaced him in the senior side against Sydney in round 17 of the 2015 AFL season.

[14] Simpson was happy with Barrass's performance, saying "it's good to get exposure in such a big game", and noted the side's scarcity of key defenders after Will Schofield injured his calf.

[16] He retained his spot for the majority of the second half of the season,[14] culminating in a 2016 AFL Rising Star nomination after a twenty-nine point win against Adelaide in round 23.

[22] Ahead of the 2017 AFL season, Fox Sports journalists Riley Beveridge and Ben Waterworth named Barrass 'the rising star' at West Coast and a 'lock' in their defence.

[22] During pre-season training, Barrass fell awkwardly after a marking contest and was dazed for roughly a minute,[25] but returned later in the week on a lighter program.