2. Keirrison (Barcelona)
This signing has to go down as one of the worst signings by Pep Guardiola although the blame has to mainly go to the president of the Catalans for overseeing this transfer. The club spent a fee of £10.5 million which is a huge transfer fee considering that no one had heard of the Brazilian that time. The transfer was a failure as the player failed to make a single appearance for the Spanish giants.
The Brazilian forward was loaned out to a couple of clubs Benfica, Fiorentina, Santos, Cruzeiro and Coritiba before finally leaving the club.