The Tricky Trees have been holding talks with Cincinnati over a loan move with an obligation to buy.
Brenner wants to make the move and is now training by himself as he waits to see whether Forest can thrash out a deal with Cincinnati.
The MLS side’s coaching staff were involved in the decision for him to train separately; he did not train at all on Sunday.
Brenner made 32 appearances across all competitions for Cincinnati last season, scoring an impressive 18 times and providing six assists.
The Brazilian has been on the books at the American team since the winter of 2021.
He is keen to now grab the opportunity that a move to Nottingham Forest represents, but the clock is ticking on the window.
Brenner, who operates as a striker, has been capped by Brazil at international youth level.
