Reading are awaiting a verdict on defender Amadou Mbengue after his early withdrawal against Millwall on Tuesday.

The 21-year-old made his first start since his return at the Den as a young Royals side romped to a 4-0 win over the Lions in the first round of the Carabao Cup.

However, the Senegal international was withdrawn after a nasty clash of heads with Murray Wallace.

Battling on for another 15 minutes, both Wallace and Mbengue were substituted before the half-hour mark with bandages.

Speaking on his availability at Port Vale on Saturday, boss Ruben Selles hinted at a possible concussion.

"The doctor took him," he said. "It was not that clear that there was a concussion. He went into some duals, but I made the decision that I could not risk life with any of my players. We are waiting for the diagnosis from the medical department."

Fellow summer arrival Sam Smith is missing for two months after injury his quad during pre-season.

Taking to social media, he said: "Gutted to be missing the first two months of the season with an injury. Not the start I’d imagined but I’ll be working hard to be back playing for Reading as soon as possible."