The central midfielder has enjoyed productive loan spells with Charlton Athletic, Swansea City and West Bromwich Albion throughout the divisions in recent years.
However, it was his season-long loan spell in the Premier League with Crystal Palace in the 2021-22 campaign that Gallagher enjoyed his best football, after scoring eight goals and registering three assists under Patrick Vieira.
Such form led to the 22-year-old being handed his England debut by Gareth Southgate in November, before earning three further caps for his country in March and earlier this summer.
Several top-flight clubs have retained an interest in signing Gallagher on loan ahead of the new season, and with competition for places fierce at Stamford Bridge, the midfielder has revealed his discussions with Tuchel to find out about his first-team opportunities for the coming 12 months.
Speaking in a recent interview, Gallagher said: "It was a phone call. I told him that I think that I'm ready to play for Chelsea. I said: 'You know that's what I want to do'.
"I've got older brothers and if you've got something you want to say or ask then you just ask because managers aren't scary. They want to talk to their players. They want to know what your thoughts are and what you think.
"We both got out of the call what we needed and it was clear after that. He wants me to prove myself in pre-season and hopefully be part of the squad."
Gallagher is a product of the club's academy and has grown up as a Chelsea fan, but has failed to make an appearance for the first team up to this point.