Chelsea teenager Billy Gilmour will be out of action for up to four months after undergoing surgery on a knee injury according to reports by Sky Sports.

The 19-year-old Scottish midfielder injured his knee early in The Blues’ 3-2 London derby victory over Crystal Palace at Selhurst Park on Tuesday evening and it was determined that the player required surgery to correct the problem.

It has been reported that Gilmour has today gone under the surgeon’s knife and the midfielder could be unavailable until early November.

Gilmour is one of a handful of Chelsea youngsters who have thrived under the guidance of Blues boss Frank Lampard this season. The midfielder made his senior debut for the South West Londoners in the 2-2 draw with Sheffield United at Stamford Bridge in August. The player has since gone on to add a further 10 first team appearances to his tally. Gilmour is still searching for his first Chelsea goal.

Chelsea agreed to sign Gilmour from Rangers when he was just 15 years old. The Blues are thought to have paid around £500,000 for his services. The player had been a shining light for The Blues’ Development Squad before finally breaking into the first team this season.