England captain Alastair Cook will play in Essex's first four County Championship games of the season.
Cook will return to action for the first time since the disastrous winter tour of Australia when Essex play Cambridge MCCU in a warm-up match on Monday.
The ECB has then made him available for Essex's four-day matches against Derbyshire, Gloucestershire, Surrey and Leicestershire.
He will also play in Essex's opening T20 Blast game of the season against Middlesex Panthers at Lord's on Saturday, May 17.
Cook missed the pre-season friendly with Kent this week to attend the birth of his daughter.