Arsene Wenger has been rocked by the news that starlet Conor Henderson will be out for at least six months after damaging his cruciate ligaments.
The 19-year-old midfielder was on the verge of breaking into the first team at the Emirates this term but this injury will have checked those plans.
Henderson played in the friendly against Cologne over the weekend and was stretchered off with a knee injury towards the end of the 2-1 win.
Arsenal's medical team were keen to assess the injury as soon as possible and tests have shown that the young Irishman could miss the entire season.
"Conor has a knee injury and it looks as if it is a cruciate," Wenger told Arsenal.com.
"That means unfortunately that he we will be out for six months at the very least."
Henderson added on Twitter: "I have damaged my ACL and lateral meniscus and will miss rest of season. I'm absolutely devastated but am determined to come back stronger!"