Nothing will kick Europe's top clubs into gear quite like the news that Lionel Messi will leave Barcelona.
Plans for the transfer window would have been long-standing in most cases, but the Argentine icon being available as a free agent is a turn of events that didn't seem likely with negotiations between the player and Barcelona seemingly progressing well in recent weeks.
But in a three paragraph statement, the Spanish side started the transfer merry-go-round. 'Messi shall not be staying on at FC Barcelona,' the club confirmed.
The likes of Harry Kane and Romelu Lukaku have been linked with huge-money transfers, but clubs may decide they can use that money on wages to tempt Messi to join instead.