Allan Lamb was often unavailable for Northants

"If somebody is going to play less than a quarter of the season then frankly it's not viable," Coverdale told BBC Sport Online.

"We found this even before the days of central contracts when we had players like Allan Lamb missing roughly 50 per cent of the season.

"We might want to get quality players and we all want heroes but in the end a top quality player - while they can stimulate a lot of interest - can be a limited influence on the field."

Warwickshire chief executive Dennis Amiss believe the structure of county cricket should be adjusted to ensure clubs get more value out of their prime assets.

He said: "There should be eight four-day matches - where all the England players are involved.

"The rest should consist of a three-day championship played in one division open to the non-England players."

This system, Amiss believes, would prevent the threat of cricket being reformed at a regional level whereby Lancashire, Durham and Yorkshire - for example - would be amalgamated to create 'the North.'

Andy Caddick's Somerset appearances are limited

"The eight matches would be played when you don't have Tests so all your best players are playing against one another," he added.

But Coverdale questioned whether there was enough time in the domestic calendar to stage such matches.

He said: "The structure of the season is important but it won't make any difference to the international cricketers.

"Such is the volume of cricket in all the world it's essential that England players have the right preparation for international matches.

"I'm sure that after the summer Tests are over next year the England players will need a break.

Benefits question

"They'll have the Ashes series, the World Cup and so on round the corner."

Although Coverdale in general feels the central contract system is helpful - because at least counties then know how much they'll get from England players - Amiss sees another problem.

"As England players go on, they come towards their benefit," he said.

"But when they finally have their benefit season they are going to get less money because the fans won't have seen them play at all."