Byas, 38, appeared to have called a close to his 15-year first-class career after leading the Tykes to their first County Championship in 33 years last season.

The opening batsman said at the time he wanted to quit while "still at the top".

Speaking to BBC Radio, Byas hinted that he had been pushed into retirement sooner than he would have wished.

"The decision made in September wasn't only mine," he said, "although I don't want to go further into that.

"I was happily retired but after a little persuading, I see the prospect as an exciting challenge.

"I'm looking forward to joining up with the squad and hopefully my experience will complement the promising younger players at the club."

Byas has 14,398 first-class runs to his name at an average of 35.37.

"Hopefully the signing of David will provide some experienced competition at the top of the batting order," said cricket manager Mike Watkinson.

"Although we are firmly committed to developing the best young players within the county, the services of David will help provide some short term stability to the squad."

Crawley move

The announcement looks likely to increase John Crawley's chances of ending his contract with the Red Rose county.

The 30-year-old recently failed to win his release when the England and Wales Cricket Board ruled that Lancashire were not guilty of breaching their agreement with him.

Byas is not the first Yorkshire captain to end his career elsewhere - Brian Close moved to Somerset after that 1968 Championship win and Raymond Illingworth joined Leicestershire.

But the former skipper's move to Yorkshire's Roses rivals is unprecedented.

"I've just spoke to David and wished him well," Yorkshire chief executive Chris Hassell told BBC Sport Online.

"I think its due to the Crawley issue that Lancashire find themselves in pretty desperate straits.

"He's a talented player and, having retired, it must be a huge fillip to have someone call him up and ask him to help them out."