'In a sense Koeman’s failure at Everton says little about how he would fare at Barcelona, but scar tissue tends to accumulate and it will, understandably, count against him. It’s not a coincidence that he has never looked better as a manager than he did at Ajax when they won the league in 2004. In that regard, his career has never fully recovered from a tackle by Zlatan Ibrahimovic on his Ajax team-mate Rafael van der Vaart in a friendly between Sweden and Holland in August 2004. Van der Vaart was injured and blamed Ibrahimovic, exposing fault-lines in the dressing room and placing pressure on the already fraught relationship between Koeman and his sporting director, Van Gaal. Ibrahimovic was sold to Juventus in the ensuing mess and, without a striker, Ajax collapsed.
Koeman resigned the following February and, although he won the league with PSV two years later, it feels as though he has been seeking another Ajax ever since.' Guardian