The 21-year-old joined Chelsea from Borussia Dortmund last summer for a reported £48.5 million fee but struggled in his first season.
Gittens scored just once and provided five assists in his 27 games across all competitions as a persistent hamstring issue killed any kind of momentum.
Chelsea have since made the record £117 million signing of long-term target Morgan Rogers, a player who also likes to play on the left.
Speaking to The Athletic, Gittens welcomed the addition of Rogers, saying: “Everyone is very positive, looking forward to the new season and to be better and to succeed, which is the main thing.
“We want to win everything — that is our ambition: to win the Premier League, the FA Cup and win anything that we’re in. Bringing in a player like Morgan will hopefully raise the bar to win titles.
“Our quality (to challenge Arsenal for the title) is there. As a team, we have individuals on the pitch who can do amazing things but we have to try and put that together.”