Liverpool have been thwarted in their first official move for Stewart Downing after Aston Villa rejected a £15m bid for the England international.

The Anfield club made their opening offer for the 26-year-old on Tuesday in an attempt to address a frustrating summer in the transfer market so far but were immediately rebuffed by Villa, who value the winger at closer to £20m but are reluctant to sanction his departure.

Downing has encouraged Liverpool's interest by announcing he has no intention of extending a Villa contract that has two years remaining. Villa, as Liverpool know following their long and failed pursuit of Gareth Barry, are tough negotiators under the chairman Randy Lerner and after losing Ashley Young to Manchester United it may take a much bigger offer before they countenance Downing's sale.

Villa received £16m from United for Young, who had 12 months remaining on his contract and whose form was eclipsed last season by Downing, their player of the year. It is therefore no surprise that Liverpool's opening gambit failed, although Fenway Sports Group, the club's owner, is expected to return with an improved offer for a player that the manager, Kenny Dalglish, has made a transfer priority.

The striker David Ngog, who rejected the makeweight role in Liverpool's acquisition of Jordan Henderson from Sunderland, could be offered to Villa on top of a cash bid.

Despite signing Henderson prior to the European Under-21s Championship Liverpool have struggled to land several leading targets – including Young, Phil Jones and Connor Wickham – and are yet to agree a price with Blackpool for Charlie Adam. Their difficulties have been compounded by a lack of interest in several high-earning yet unwanted players at Anfield, with Alberto Aquilani, Joe Cole, Christian Poulsen, Paul Konchesky, Milan Jovanovic, Brad Jones, Philipp Degen, Nabil El Zhar and Emiliano Insúa all still on the club's payroll.

Jovanovic, at least, appears to be edging towards an Anfield exit one year after he arrived on a free transfer from Standard Liège and proceeded to collect £120,000 a week. The Serbia international made two appearances under Dalglish and FSG is understandably keen to remove him from the wage bill to release funds for other targets. He has been linked with a move to Olympiakos and was quoted in the Greek media as saying: "I got the paper from Liverpool that I am free to search for a new club. Up to now, I still haven't received an official offer from Olympiakos, but I am looking forward to hearing their plans."

Steven Gerrard, meanwhile, is expected to be fully fit for the start of the new Premier League season on 13 August despite being withdrawn from Liverpool's pre-season tour of the Far East. The Liverpool captain underwent two groin operations in the second half of last term, ending his involvement in March, and remains on a rehabilitation programme.

It has been decided to avoid interrupting that by withdrawing the 31-year-old from the trip to China, where Liverpool play Guangdong next Wednesday, and Kuala Lumpur, where they face a Malaysia XI on 16 July. The squad will also take part in a training session in Singapore the following day.

Dalglish said: "Steven and the medical team have done fantastically well so far and they are in the final stages of getting him back to full training. I'm sure there will be supporters disappointed that Steven is unable to be with us in Asia but I'm sure the same people will appreciate the importance of Steven giving himself the best possible opportunity of being fit to play against Sunderland on the opening day of the new campaign. Steven continuing his rehabilitation programme at Melwood is in everybody's long term interests."