The 35-year-old Finn, who is not being retained by Sauber ahead of their takeover by Audi, told reporters at the Qatar Grand Prix that there was still "a bit of work to do" as he contemplates his future.
He declined to say it was his best option, but added: "It is a really solid option and I really appreciate what Toto (Wolff, Mercedes team chief) said last weekend. There's still a bit of work to do to finalise some things.
"It's been a while that I'm now in the situation that I can decide yes or no on some different things so I just want to wait at least few more days, or one or two weeks -- probably to get over with the season, then sit down and we'll see."
Bottas will be replaced at Sauber-Audi by Formula Two championship leader Gabriel Bortoleto.
Wolff was quoted last weekend saying he felt it was only "a matter of time" before a reunion with Bottas, who won 10 Grands Prix during his five years at Mercedes alongside Lewis Hamilton from 2017 to 2021.
Bottas added: "The priority for me is still F1, I feel like I'm not done yet so I think that to be around, do some testing, gives me a chance for a seat in 2026. In this sport, you just never know what's going to happen.
"There's also a new team joining which means two more seats, so it increases the opportunity."
The expected arrival of Cadillac will likely lead to more movement in the drivers' market next year, with the General Motors' brand expected to consider experienced drivers for their inaugural season.
Bottas has started 243 Grands Prix.
Mercedes will change their line-up next year following seven-time champion Hamilton's switch to join Ferrari -- George Russell will remain with Italian teenager Andrea Kimi Antonelli replacing Hamilton.
Schumacher, 25, son of seven-time champion Michael Schumacher, has been Mercedes' reserve for two years after spending two years with the Haas team.
The German said he will focus on his continued role as a driver with the Alpine team in the World Endurance Championship and the Le Mans 24 Hours race.
