PHOTO: Semi Ajayi in training with the Arsenal first team

The 21-year-old was pictured racing Per Mertesacker to the ball during practice with the Gunners.

Arsenal's injury crisis in defence has been well documented this season. The absences of French duo Laurent Koscielny and Mathieu Debuchy, in particular, at centre-back and down the right have been especially detrimental.

So what can boss Arsene Wenger do to solve the crisis?

For a start, the Frenchman could restore Calum Chambers to central defence and play Hector Bellerin at right-back. Aside from that, however, there seems a shortage of options.

But could that be where 21-year-old Semi Ajayi comes in?

The young defender has already featured on the bench this season and was pictured in training with the Gunners on Friday afternoon.

Next to the 'big friendly German' Per Mertesacker, Ajayi was seen running to claim a ball in practice.

Is the youngster set to feature on the bench once more against Manchester United this weekend? It would certainly be a tough test for the 21-year-old. But such is Wenger's threadbare back four right now that he could be a promising alternative for Arsenal to turn to.

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