Raul Jimenez was stretchered off the field in the early stages of Wolves' Premier League match against Arsenal after suffering a head injury.
The striker clashed heads with Arsenal centre-back David Luiz during an aerial challenge in the Wolves box after a corner from Willian.
The incident happened just five minutes into the encounter, but a lengthy delay followed as the players received treatment.
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The 29-year-old seemed unresponsive as medical staff checked on him and the Mexico international had to be carried off the field 10 minutes later and was replaced by Fabio Silva.