Matthew Upson is the subject of strong interest from Liverpool and could move to Anfield from Birmingham City when the transfer window opens in January.

England international Upson has not played for Birmingham's first team since February because of an Achilles injury but Liverpool have been keeping an eye on his rehabilitation.

He returned to action for the reserve team on Wednesday night and Birmingham, bidding to reclaim their lost horizon, have dropped enough hints to suggest that they will sell the player if a club comes in offering a fee in the region of #4 million.

Liverpool have suffered defensively this season — they have lost five matches already — and need a left-sided centre back in a bid to make up ground in the race to finish in the top four.

It seems likely that Upson will be signed to challenge Sami Hyypia, whose best days are probably behind him.

If Upson moves to Liverpool, he will re-join Jermaine Pennant, who left St Andrew's for Anfield in the summer. Both were also team-mates at Arsenal.

David Sullivan, the Birmingham co-owner, recently emphasised the club's problem concerning their most prominent players. Not only is Upson likely to leave, but David Dunn could also make a return to the Premiership, probably for about #1 million.

Upson has 19 months left of his contract and Birmingham would rather sell him now than risk losing him for nothing on a free transfer.

"Matthew Upson is a great player but he wants to go to a bigger club and unfortunately we can’t keep him," Sullivan recently said. "We have already invoked a one-year option in our favour to keep him until now but he won’t renew, as much as we would like him to."

Upson, aged 27, is at the stage of his career where he should be reaching his professional peak.

He represents one of Steve Bruce's best signings — he joined Birmingham for #1 million from Arsenal in January 2003 — and has played seven times for England.

His most recent match for Birmingham came on February 4, 2006, at home to Arsenal. He was withdrawn in the 88th minute and was initially ruled out for the remainder of the calendar year.

He could be ready for first-team action next month. If he does play for Birmingham and appears to be over his injury, Liverpool are sure to make an offer to take him back into the Premiership.

That would be ideal for Upson, who has endured a wretched 2006 and who would want to return to the England squad. Playing in a Liverpool team that adopts zonal marking, Upson would certainly have opportunities to impress. Liverpool also offer Uefa Champions League football.

Bruce recently said: "Of course, we want our best players to remain at the club and Matthew Upson comes into that category. I will try my utmost to keep him but I am not going to lie or pull the wool over anyone's eyes. It is Matt's prerogative is to keep his options open."

Dunn could return north to Blackburn Rovers, where he made a name for himself as a talented winger and earned international recognition.

However, a succession of back and hamstring injuries have diminished him. He will probably leave for about #1 million.

The inevitable departure of two key players spell the latest chapter in Steve Bruce's revolution. Whereas his Birmingham squad was once packed with ageing, famous players, now it is packed with younger, hungrier players.

Upson and Dunn have never given less than 100 per cent effort and they remain popular among supporters, but they have too much talent for the Coca-Cola Championship. They were signed for a higher level of football and are paid accordingly.

Birmingham's wage bill has been significantly reduced in recent months and, while the club remains in profit, there is no desire to throw money around like they did two or three years ago.

Birmingham will play Southend United at Roots Hall on December 23 (3pm). The date of this fixture has been changed for the second time this season but will now take place on its original date.

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