4. Iago Aspas (Liverpool)
37 goals in 75 matches for Celta Vigo put Iago Aspas on the shopping window and Liverpool felt they had unearthed a precious gem when they snapped him up in 2013.
Though many fans expressed their reservations over the rationale to sign a relatively unknown player, Liverpool's manager Brendan Rogers was adamant that Aspas was going to be a success in England.
But it turned out to be the opposite as the Spaniard failed to get going and played second fiddle to the other strikers in the team throughout the season.
One goal in seven matches was the return on investment for Aspas, which was obviously not good enough. A loan move to Seville followed in 2014 and then a permanent move back to Celta Vigo a year later.
Back at his natural habitat, Aspas returned to his scoring ways as he netted 26 goals in 49 appearances in his first season back and 23 goals in 37 appearances last season.
His goal-scoring exploits saw him win his first cap for Spain in 2016 and he went on to feature in the 2018 World Cup in Russia.