[5] When first-choice goalkeeper Darren Randolph had to miss the visit to Blackburn Rovers in October 2014 through suspension and previous third-choice Nick Townsend's loan had no recall clause, Trueman was given a squad number and a place among the substitutes;[6] he remained unused.

[10] He made his first appearance of the season in a matchday squad on 30 April, at home to Middlesbrough, when Adam Legzdins took over in goal after Tomasz Kuszczak underwent surgery on a broken nose, and kept his place on the bench for the last match of the campaign, away to Cardiff City.

[16] When Stockdale returned to the starting eleven in November, manager Steve Cotterill retained Trueman in the matchday squad,[17] but when Garry Monk took over in March, he recalled Kuszczak to the bench.

[20] He made his Football League debut in the starting eleven for the opening match of Birmingham's 2018–19 season, a 2–2 draw at home to Norwich City in the Championship,[21] and despite the arrival of the experienced Lee Camp kept his place for the visit to Middlesbrough.

He performed well enough to keep his place,[28] and held it for ten matches, but after he and the team conceded five goals to Leeds United and then three against Hull City,[29] Camp was recalled for his ability to organise his defence[30] and retained for the rest of the season.

[33] Trueman was an unused substitute for Birmingham once in mid-January in the absence of regular backup goalkeeper Andrés Prieto,[34] and on 1 March, he joined League One club Swindon Town on an emergency loan.

[7] Having been a regular on Birmingham's bench as backup to loanee Matija Sarkic in the 2021–22 season while Etheridge recovered from COVID-19,[7][36] Trueman joined League One club Oxford United on an emergency loan on 23 November 2021,[37] and played twice.

He was used once, playing the last 20 minutes of the visit to Nottingham Forest in April 2022 after Etheridge was knocked unconscious in collision with Djed Spence; he conceded shortly after coming on, as Birmingham lost 2–0,[40] and Zach Jeacock took over the starting role for the next two matches.