Striker Rhian Brewster was elevated to Liverpool's Under-23s after making his debut for the Under-18s in October 2015. He has made rapid progress through the ranks culminating in sitting on the first team's bench in the 2-1 defeat to Crystal Palace on 23 April 2017. Before joining Liverpool he had been at Chelsea's academy. In May 2017 he helped England under 17's to the European championship final. Brewster's 2017/18 season was cut short when he suffered ankle ligament damage in January ruling him out for the rest of the campaign. Such was his progress that he signed a five-year deal in June 2018. Media also reported that manager Klopp was so incensed by approaches from Borussia Monchengladbach that he cancelled plans for a pre-season friendly against the German side. 

2018/19 was extremely frustrating to Brewster, with the ankle injury taking longer than anticipated to recover from. He made only two appearances in Premier League 2, but Jurgen Klopp still had sufficient faith in him to put him on the bench for the second leg of the Champions League semi-final with Barcelona.

Brewster impressed in pre-season bit his opportunities were limited when competitive action got underway. He was limited to two starts in the League Cup and an eleven minute substitute appearance against Everton in the FA Cup. On 7th January 2020 he was loaned to Swansea City, joining up with his former England Under 17 coach Steve Cooper. He impressed in South Wales, scoring ten times in twenty games to help the Swans to the play-offs. After an impressive performance in a pre season friendly in Salzburg, in which he scored twice, Brewster came off the bench late on in the Community Shield but his penalty miss in the shoot out was decisive. Brewster was sold to Sheffield United on 2 October 2020 for £23.5 million. He failed to find the net in 27 appearances as the Blades were relegated at the end of 2020/21.

Staring 2021/22 in the Championship, Brewster was more promising but after three goals fourteen appearances, which earned him an England U21 call up, he missed the second half of the season with a hamstring injury. The same bad luck got him in 2022/23 when a hamstring problem sustained in November ruled him out for the remainder of the season. The Blades were promoted and he remained at the club for the Premiership campaign. It was a frustrating season for both club and player. They finished rock bottom of the Premier League, winning just three games all season. Brewster failed to find the net in any of this thirteen appearances, ten of which were as a substitute. During 2024/25, when his club were defeated in the play off final, he appeared more often, making 36 league appearances. Brewster scored four times, the most crucial being the only goal in a 1-0 win at city rivals Sheffield Wednesday. His contract was not renewed and he signed a two year deal with Derby County.