Former Newcastle United manager Glenn Roeder has been appointed managerial advisor at Stevenage until the end of the season.
Stevenage chairman Phil Wallace told the club website: "Darren Sarll is an excellent young coach who has the respect of the players and understands the DNA of the club but obviously has limited experience as a professional manager.
"Rather than throw away his energy, dedication and skill set to get results, we are instead introducing top-level managerial experience and tuition to the management structure and Glenn, having managed in the Premier League, is a fantastic addition to our team.
"Glenn will start today and will be at the heart of everything we do until the end of the season. We hope this exciting appointment gives the whole club a lift and sees us start to climb the table in our remaining nine games."
Stevenage are only one place but seven points above the relegation zone in League Two.
Last year Roeder also took on an advisory role with Championship side Sheffield Wednesday.