Liverpool had to agree terms with first division Blackburn Rovers for Platt even though he was then playing for Oswaldtwistle Rovers in the Lancashire Combination. Blackburn still held his League registration so when Platt wanted a return to the League interested parties had to settle a contract with his "former" club. Twenty-year-old Platt took over from Bill Perkins in the Liverpool goal for the last seven League games of 1902/03, having already been picked 15 times earlier in the season. He started the 1903/04 season as first-choice but was replaced by Charles Cotton after 18 matches. Platt won his place back for the last three fixtures of that campaign but never represented the club again. When the next season started on the first day of September 1904, Ned Doig was between the sticks. While at Liverpool Platt was said to be still engaged at his trade as a cotton weaver. Peter Platt passed away only 39 years of age in a mini-flu epidemic in Nuneaton in 1922.