Birmingham manager Steve Bruce is resigned to Matthew Upson being sidelined for at least six months after it was confirmed the central defender had suffered a ruptured Achilles.
Upson will undergo surgery tomorrow after a scan had confirmed Bruce's worst fears about the former Arsenal player who sustained the injury during the warm-up before Sunday's derby with Aston Villa.
The England player had been set to make his return to action following two months on the sidelines with groin and pelvic problems.
But now he has been ruled out until at least October by Bruce, who had been hoping Upson's ability and experience would have been available for the finale of the battle to survive in the Premiership.
Upson's setback also ends any possibility of him being off-loaded in the summer should City be relegated after attracting the interest of Liverpool earlier in the campaign.
Bruce said: 'I feared the worst on Sunday and it has been confirmed that Matthew has ruptured his Achilles. Of course, we are keeping our fingers crossed he can return as soon as possible but you are looking at six months out.
'It is terrible news, a real blow for us and the player and he is booked in to have surgery tomorrow.
'We had eased Matthew back carefully after his other injuries and had hoped he would be available for the finale to the season.
'Over the last three and a half years he has been a big, big player for us in establishing Birmingham in the Premiership and being given his England chance.
'I have always maintained he is the best naturally left-sided central defender in the Premiership and he has been immense for us.
'Our thoughts are with him now but he is a strong character and let's hope he can get back as quickly as possible.'
Upson's continued enforced absence means that Martin Taylor is likely to deputise for the remainder of the campaign alongside Kenny Cunningham - starting with tomorrow's home clash with his previous club Blackburn.
But former Blackburn midfielder David Dunn will almost certainly be unavailable with the calf injury sustained in the first half against Villa and leading scorer Jiri Jarosik is given only a 50-50 chance of recovering from a hamstring injury.