Somerset have confirmed that Jos Buttler is leaving the club and Sky sources understand he will be announced as a Lancashire player next week.
Taunton-born Buttler came through the ranks at his home county and has played for England in T20 and ODI matches.
Buttler admits it was a difficult decision to leave Somerset but insists a move will help him progress in his career.
"I am very sad to be leaving Somerset but feel it is a decision I must take in order to develop my expertise as a wicketkeeper," he told the club's official website.
"I am immensely grateful for all the help and support that everyone at Somerset has given me which has shaped the player and person I am today."
Somerset CEO Guy Lavender said: " Both Jos and the club have worked extremely hard over the last few months to find a solution, which satisfies Jos's understandable desire to have more time behind the stumps in order to advance his international career.
"I would like to make it clear that he has behaved impeccably during this difficult process.
"However, the club, on a matter of principle and pragmatism, feels unable to offer a guarantee to Jos - or any other player - of selection in their preferred role.
"Such a situation would be unfair on team-mates as well as those selecting the side.
"We thank Jos for all he has done for the Club and wish him well in the future."