Alan Pardew has made his third signing of summer, bringing in Siem de Jong from Dutch giants Ajax
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Ajax have been fined €25,000 by UEFA after fans displayed an offensive sectarian banner at their Champions League home game against Celtic.
The Amsterdam club also confirmed another case is ongoing concerning crowd trouble at the return fixture in Glasgow.
Ajax striker Bojan Krkic has been ruled out for up to six weeks with a hamstring injury.
The 23-year-old, on loan to the Amsterdam club from Barcelona, sustained the injury early in Ajax's 6-0 thrashing of Go Ahead Eagles at the weekend and could now be out until the middle of November.
Atletico Madrid have won the race to sign Ajax's Belgian centre-back Toby Alderweireld, who had previously been linked with Liverpool and Norwich.