Pollock was a trainee with
Leeds United up until
under-15 level, where he was considered a
midfielder. He was called up to the first-team bench by manager
Michael Jolley for the first time in October 2018. Pollock made his professional debut on 29 December, coming on as a 52nd-minute substitute for
Martyn Woolford in a 2–1 win at
Exeter City following a red card for centre-back
Alex Whitmore. He turned professional in February 2019 and upon signing a -year deal said that "my ultimate ambition is to be the best central defender in the world and play at the highest level I can". Pollock was given his first start for the "Mariners" on 13 August 2019, in a 1–0 victory over
Doncaster Rovers at
Blundell Park. He scored his first goal for Grimsby in a 1–1 draw with
Carlisle United on 24 October 2020.
Watford On 27 May 2021, Pollock joined
Watford on a five-year deal for an initial fee of £250,000. On 30 August 2021, Pollock joined
Cheltenham Town on loan for the 2021–22 season. Pollock scored his first goal for Cheltenham in the
FA Cup first round against
Gillingham on 6 November 2021. He also scored in the replay win on 16 November, earning Cheltenham a spot in the second round and praise from manager
Michael Duff. Pollock made his Watford debut on 23 August 2022 in a 2–0 home defeat to MK Dons in the second round of the EFL Cup, and his full Championship debut on 19 October 2022 in a 3–0 away defeat to
Millwall. He was loaned to
Scottish Premiership club
Aberdeen in January 2023. His first goal for Watford came in the 5-0 win over
MK Dons in the
EFL Cup in August 2024. In March 2025 he was in the EFL sky bet team of the week for both the championship and EFL team of the week. Pollock was voted the Watford Player of the Season for the 2025/26 season, collecting his award at home against
Coventry City on 2nd May 2026. ==Personal life==