Negotiations are likely to go down to the wire, as clubs seek the best possible deals. Here's a look at some of the high profile deals - some likely, some less so - that could happen before the transfer window closes.
1. Philippe Coutinho - Barcelona
Barca are set for a busy deadline day, and are said to be ready to cut his loan deal at Bayern Munich short to slash their wage bill. A return to the Premier League just might be on the cards. (Photo by RONNY HARTMANN/AFP via Getty Images) | Getty Images Photo: RONNY HARTMANN
2. Thomas Lemar - Atletico Madrid
Bayern Munich are eager to sign him, but Arsenal could well look to hijack the deal late on. He's looking to revive his career after an underwhelming spell in Spain. (Photo by GABRIEL BOUYS/AFP via Getty Images) | Getty Images Photo: GABRIEL BOUYS
3. James Rodriguez - Real Madrid
Could Arsenal pull another last-gasp, Mesut Ozil-style deal out the bag? They could well look to swoop for the Los Blancos man, and Everton are also said to be on his tail. (Photo by PIERRE-PHILIPPE MARCOU/AFP via Getty Images) | Getty Images Photo: PIERRE-PHILIPPE MARCOU
4. Matheus Cunha - RB Leipzig
Brighton & Hove Albion look set to battle it out with Wolves for the Bundesliga ace, who has netted an impressive eight goals in nine matches for the Brazil U23s. (Photo by JUAN BARRETO/AFP via Getty Images) | Getty Images Photo: JUAN BARRETO