Bristol City defender Christian Ribeiro has suffered anterior cruciate ligament damage and is facing 12 months on the sidelines.
The 18-year-old was making his first-team debut against Peterborough in the Carling Cup first round on Tuesday evening when he sustained the injury.
Ribeiro will now undergo surgery before the weekend ahead of a lengthy spell out of action.
City manager Gary Johnson told the club's official website: "Everyone is gutted for Christian.
"It is hard luck on the lad, 20 minutes into his debut. But as I said on the night, he will come back from this.
"He is young, fit and strong. He is only 18 and he has time on his side.
"It will seem a long way back at the moment but we will give him all our time and attention."

Latest Sky Sports News Report
West Ham 1-2 Everton - Moyes
Wigan 1-1 Fulham - Martinez
Wigan 1-1 Fulham - Hodgson
Hull 2-1 Stoke - Horton
Hull 2-1 Stoke - Pulis
Hull 2-1 Stoke - Bullard
Tottenham v Sunderland - 2nd Half
| Time | Fixture |
|---|---|
| Sunday 8th November | |
| Barclays Premier League | |
| 13:30 | Hull vs Stoke |
| 15:00 | West Ham vs Everton |
| 15:00 | Wigan vs Fulham |
| 16:00 | Chelsea vs Man Utd |
| Monday 9th November | |
| Barclays Premier League | |
| 20:00 | Liverpool vs Birmingham |
| Saturday 21st November | |
| Barclays Premier League | |
| 12:45 | Liverpool vs Man City |
| 15:00 | Birmingham vs Fulham |
| 15:00 | Burnley vs Aston Villa |
| 15:00 | Chelsea vs Wolverhampton |
| 15:00 | Hull vs West Ham |
| 15:00 | Sunderland vs Arsenal |
| 17:30 | Man Utd vs Everton |
| Sunday 22nd November | |
| Barclays Premier League | |
| 13:30 | Bolton vs Blackburn |
| 15:00 | Tottenham vs Wigan |
| 16:00 | Stoke vs Portsmouth |
| Wednesday 25th November | |
| Barclays Premier League | |
| 19:45 | Hull vs Everton |
| 20:00 | Fulham vs Blackburn |
| Saturday 28th November | |
| Barclays Premier League | |
| 15:00 | Blackburn vs Stoke |
| 15:00 | Fulham vs Bolton |
| 15:00 | Man City vs Hull |
| Time | Result |
|---|---|
| Saturday 7th November | |
| Barclays Premier League | |
| Wolverhampton 1 - 4 Arsenal | |
| Man City 3 - 3 Burnley | |
| Tottenham 2 - 0 Sunderland | |
| Blackburn 3 - 1 Portsmouth | |
| Aston Villa 5 - 1 Bolton | |
| Wednesday 4th November | |
| Barclays Premier League | |
| West Ham 2 - 1 Aston Villa | |
| Sunday 1st November | |
| Barclays Premier League | |
| Birmingham 0 - 0 Man City | |
| Saturday 31st October | |
| Barclays Premier League | |
| Man Utd 2 - 0 Blackburn | |
| Sunderland 2 - 2 West Ham | |
| Portsmouth 4 - 0 Wigan | |
| Bolton 0 - 4 Chelsea | |
| Stoke 2 - 2 Wolverhampton | |
| Fulham 3 - 1 Liverpool | |
| Burnley 2 - 0 Hull | |
| Everton 1 - 1 Aston Villa | |
| Arsenal 3 - 0 Tottenham | |
| Sunday 25th October | |
| Barclays Premier League | |
| West Ham 2 - 2 Arsenal | |
| Man City 2 - 2 Fulham | |
| Liverpool 2 - 0 Man Utd | |
| Bolton 3 - 2 Everton | |
Join skysports.com football editor Mark Buckingham to debate Chelsea's 1-0 win over Man Utd.
Sunderland fan Lucinda Gittins was strutting her stuff in the Soccer AM studios this week.
Paul Merson fears for Phil Brown - and says Hull couldn't be facing a worse game than home to Stoke.
A John Terry header proved the difference as Chelsea beat Manchester United to move clear at the top of the Premier League.
Follow all of Sunday's action via skysports.com's Score Centre, including Chelsea versus Manchester United.
Hull came from behind to beat Stoke 2-1 at the KC Stadium to ease the pressure on Phil Brown.
League One leaders Leeds United will travel to Kettering whilst Norwich will face Carlisle or Morecambe.
Fulham stayed strong and held firm at Wigan to keep the Latics at bay and come away with a hard-earned point.