Sam Allardyce has opened the door for Roque Santa Cruz to leave Blackburn Rovers, but only if he sees out the season at Ewood Park and helps to keep the club in the Barclays Premier League.

The Blackburn manager is battling to keep hold of the Paraguay striker after rejecting an improved £16 million bid from Manchester City, but Mark Hughes, Allardyce’s opposite number, is preparing a third offer for the 27-year-old, whom he signed for Blackburn in a £3.8 million transfer from Bayern Munich in July 2007.

Allardyce insisted that Blackburn will consider selling Santa Cruz only if City “blow us out of the water” with a huge bid. However, he hinted that he will be ready to offload his prized asset at the end of the season.

“My message on Roque is that we simply want him to stay with us, get fit, help Blackburn stay in the Premier League and then see what the summer brings,” Allardyce said, describing the transfer window as “one of the most destructive times of the season”.

“It’s unproductive and creates mayhem, inflation and unrest,” he said. “There will always be a price on a player, but at the moment we cannot put a price on his head. The simple fact is that, rather than accept X amount of millions for him, he is much more valuable to us staying at the club than any money we would get for him.

“Unless Manchester City blow us out of the water, it is going to be very difficult to replace Roque with a player of similar quality.”

Blackburn travel to Fulham today attempting to claim the three points that could take them out of the bottom three, with City only four points ahead of them, Allardyce said that there would be no sense in selling Santa Cruz — still sidelined with a calf tear — to a relegation rival.

“We have already let City off the hook by allowing them to come from 2-0 down to get a draw against us last month,” he said. “So we don’t really want to help one of our closest rivals again by selling one of our best players to them. We are both in a battle for survival and that has to be taken into consideration.

“Roque only signed a new contract at the start of this season, so I don’t see a problem if he is still with us once the window closes. If that happens, players just get on with doing what they are doing and we can then see what the summer brings.

“I can’t second-guess what Manchester City are going to do next, but Roque is still our player and I just want him fit to take part in our relegation battle.”

Blackburn are unbeaten in three league matches under Allardyce, who succeeded Paul Ince on December 17, but he said that extending that record against Fulham will be tough. “Roy Hodgson has done a terrific job there and they are unbeaten in nine league games,” Allardyce said. “It won’t be easy for us.”