During pre-season, Santos played an active part for Chelsea during their tour of the United States, the initial suggestion being that he would feature in Mauricio Pochettino's first-team squad.
However, the decision was taken to allow the 19-year-old to make the temporary switch to the City Ground in the hope of gaining regular Premier League football.
Instead, Santos was provided with just one start - which came in an EFL Cup defeat to Burnley - and one brief substitute outing against Liverpool in the Premier League when Forest were already 3-0 down.
As expected, Chelsea activated their recall clause at the beginning of January, and conversations will soon be taking place over where the Brazil international should spend the second half of 2023-24.
No decision is expected anytime soon courtesy of Santos now being away with Brazil Under-23s, who are participating in the CONMEBOL pre-Olympic tournament.
Being back in South America, that gave Santos the chance to speak to Globo, where he addressed his time at Forest and commented on how he has adapted to English football.
Santos said: "It was my choice. Unfortunately it wasn't how we all imagined. I imagined that I was going to play and so on, I was always ready, always well, but it was the coach's choice, and I respect it.
"I continued working and, thank God, I'm back at Chelsea, ready to do my best in any team I'm in."
On England's top flight, he added: "I think it took me a little while to adapt, I think a month, it was the speed of the game.
"It's very different, Premier League people are very intense, very fast, very strong. I think it took me a month to adapt there, but today I'm calm about it."
With Chelsea having already filled their seven foreign loan slots, a temporary switch to another Premier League side or Championship club appears to be the most likely solution.
As it stands, six players - Moises Caicedo, Enzo Fernandez, Conor Gallagher, Lesley Ugochukwu, Carney Chukwuemeka and Romeo Lavia - are ahead of Santos in the pecking order.