Anderson is the DM in the Rice/Anderson combo, with Rice having the ability to play box to box. Therefore, it would be Rice that Foden would be supplanting if he was the second midfielder in that pairing, and that will never happen.
In the 4-2-3-1, Tuchel has made it clear that Gordon & Rashford are his left-sided player of the 3, while Saka & A.N.Other are his right-sided player of the 3, with Kane upfront. That leaves only the middle of the 3 for Bellingham & Rogers to fight over (per the media). Clearly, Foden can play on the right, and be a back-up to Saka, or thru the middle in place of Kane, but his favored position is in the middle of the 3, where people seem to think it’s Bellingham, then Rogers.
In addition to Foden, there are Palmer, MGW, Eze and Madueke looking for a spot. Madueke might be fortunate in that he is a natural back-up for Saka.
With a 25 man squad, and 3 keepers, that leaves only 22 outfield players for the 20 players who are considered starters and their back-ups…leaving 2 “at large” squad positions available. Personally, I think Foden is good enough and flexible enough to play all 3 roles (7, 9 & 10, esp with an overlapping RB like Reece James or Spence), but will TT spend the two picks on extra defenders, midfielders or forwards?
It wouldn’t be the worst thing in the world for City to have Phil at home with his feet up, but I know it would be gutting for him, esp given his ability to fill many holes and come up with goals, too.