According to head coach Gareth Batty, Surrey director of cricket Alec Stewart will be irreplaceable when he leaves the club.
Stewart, a former England captain, announced last week that he will stand down after 11 years at the end of the season.
During his tenure, Surrey won the County Championship three times and are currently chasing their third consecutive title.
In his 22-year playing career, Stewart scored 40,936 runs, including 67 centuries, in 951 matches for Surrey.
Batty said BBC Radio London:
"He's driven by excellence and he's done that again in a role off the field - we can't replace that."
Surrey's squad remains largely unchanged from last season, with the addition of batter Dan Lawrence from Essex.
Former England spinner Batty emphasised that the mentality at Surrey must be focused on winning, as they aim for a third consecutive title.
On Friday, 5 April, Surrey will begin defending their County Championship title away at Lancashire's Old Trafford.