Manchester United are ready to make a £5 million bid for the Boca Juniors defender Nicolas Burdisso, according to the player's agent.

On the day the Premiership side confirmed they have lined up a meeting with officials from Rennes in an attempt to finalise a deal for their left-back Julien Escude, United have also been linked with the 21-year-old Argentinian.

Burdisso played against United in the recent friendly which Boca lost 2-0. His agent Gustavo Mascardi, the same man who represented Juan Sebastian Veron when he arrived at Old Trafford for £28.1 million, claims Alex Ferguson is interested in his client. "I know about Manchester's interest and this is a negotiation that no club can let go by because it's a lot of money for a defender," he said.

Reports in Argentina claim Boca want to sell Burdisso next summer but Ferguson would only be interested if he can have the player before the August 31st deadline. One player likely to be on his way before then, however, is the 23-year-old Escude.

United's chief executive Peter Kenyon will meet officials from Rennes in Paris on Sunday to discuss a deal, despite the knee injury Escude incurred when he fell over a kerb while walking his dog. They had a bid of £2 million rejected last week but it is understood that United will increase it to nearer the £3.5 million Rennes require. "We met with Rennes two weeks ago and a meeting was planned then for this Sunday," Kenyon said.

United will take Rio Ferdinand to Chelsea for this evening's Premiership game but the club's record signing is unlikely to play as he has not fully recovered from the ankle injury he picked up in the match against Boca.

"I don't know if he'll make it," Ferguson said yesterday. "We'll wait and see tomorrow." Fabien Barthez will also miss out with a hip injury but United are hopeful that he will return for the Champions League qualifier with Zalaegerszeg on Tuesday, when they need to pull back a 1-0 deficit.

Ferguson's caution over Ferdinand is a reflection of both his desire to protect the defender ahead of Tuesday's Champions League match and his confidence in 21-year-old Irishman John O'Shea, who has deputised ably for the England international so far.

Injuries notwithstanding, Claudio Ranieri does not consider tonight to be the best time to be facing United. "They are ready, 100 per cent," said the Chelsea manager, whose side lost the same fixture 3-0 in April although earlier they won the away game by the same score. "I don't think we're ready yet," he added. "We're a good team but until we're in the Champions League, we can't really be talked about in the same breath." For his part, Ferguson said: "We have a fantastic record there. Their record at Old Trafford is fantastic over the years, and ours is equally as good down at Stamford Bridge.

"I've been here 15 years, so I've a fair input into it, and it's not just three or four years this has been going on; it's gone on for 30 or 40 years. It's certainly, without doubt, our most successful away fixture."

Ranieri's preparations have nevertheless been harmed by the participation of Marcel Desailly and Emmanuel Petit

in a friendly for France in Tunisia just 48 hours before facing United.

Although teenager Carlton Cole is an enticing future prospect Ranieri will not throw him into the starting line-up just yet.