West Ham's unable to decide about the German substitute's deal (13)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

West ‘Am is yet another way of indicating the missing H, in this case off [H]UNG for undecided (jury, election). Insert DER, the, in German, and STAND-IN substituting for -um- substitute. West Ham did decide to sign Niclas Füllkrug of Borussia Dortmund for £27m in 2024 on a 4 year deal.