At the young age of 23, Sinisalo's estimated market value stands around £678k, as given by Transfermarkt. With his contract set to run for another four years and three months, expiring on 30 June 2029, Celtic will no doubt be keen to continue benefitting from his services.
After joining Aston Villa as a trainee in July 2018, almost three years later, in September 2020, Sinisalo gained experience and playing time through a loan move to Ayr United in Scotland's Championship. The move was short-lived, as Sinisalo returned to Aston Villa in June 2021.His penchant for loans continued, as he was sent to Burton Albion in England's League One in July 2022. Despite featuring only four times in league matches for Burton during the 2022-2023 season, it gave Sinisalo valuable game time to hone his skills. After finishing his loan spell at Burton Albion in December 2022, once again he returned to Aston Villa.
A fresh loan move awaited him in July 2023 to Exeter City, another team in England's League One. It was a short stint, as a year later Sinisalo made his way to Scotland, signing for Celtic in July 2024 for a fee of around £1m.
In the current 2024 - 2025 season, Sinisalo has thus far made three first-team appearances in league matches for Celtic. He has also aided Celtic's Scottish Cup 2024 - 2025 campaign with two starts and has experienced international competition, earning a start for Finland in the Euro Qualifiers from 2022 - 2024.
While still early in his Celtic chapter, Sinisalo’s career, enhanced by experience at various clubs and featuring on international platforms, fortifies potential promise and growth in the coming seasons.
