The 18-year-old was stretchered off in the first half of the Royals’ 2-1 win at Wycombe on Saturday
Ballard, on loan from Southampton, scored a hat-trick in England Under-19s’ 7-1 win over Mexico last week
It’s a massive loss for us because he’s a spectacular player and a very good boy,” Royals manager Ruben Selles told BBC Radio Berkshire.
His patella tendon has been broken – it’s a bad injury, it’s going to take a long time, we don’t know exactly how long but probably the rest of the season.
We are working on it in collaboration with Southampton.
Ballard joined Saints as an eight-year-old and scored on his first-team debut, in a 3-0 Carabao Cup win over Cambridge United in August 2022.
Selles, then Southampton manager, also played him in their final two Premier League games last season – coming off the bench against Brighton and Hove Albion and Liverpool. He signed a deal at St Mary’s until 2026 this summer.
“Unluckily these things happen in football,” Selles added.
We wish he will have a quick recovery and he will be back healthy and he can keep healthy for the next 15 years of his career that is going to be a really good career.”
The Royals made it back-to-back wins in League One with a 5-1 victory against Carlisle on Tuesday.
It was the most calm end to a game we’ve had so far this season, that’s for sure,” Selles said.
“We can still offer more but we showed the potential we have. One month ago this game would have gone in a different direction. It’s not about names, the dressing room is putting a lot of effort together, the spirit and the good vibes are finally coming and getting results.
“We have been in a very dark place, as a team and as individuals, of course when you win, life is a bit different. I am in a better place than I was a month ago.