"I want to keep players on their toes. I want to keep them hungry and not show my hand too early."
The Gills manager made eight changes at half-time in their pre-season friendly against Leyton Orient on Tuesday.
He added: "I think they've got a good understanding that the next 10 days are going to be vital to us in picking that starting 11 come 6 August.
"They're all chomping to be in that starting 11 so it's a healthy situation."
Hessenthaler already has an injury headache to deal with ahead of Gillingham's first match against Cheltenham Town.
I'm a little bit apprehensive as all managers are. We need to make sure we get off to a good start this year
Gillingham boss Andy Hessenthaler
Having lost new signing Adam Birchall to a long-term knee injury, Stefan Payne and Dennis Oli have joined the former Dover frontman on the sidelines.
Danny Kedwell may be forced to play up front on his own for the Gills and Hessenthaler is confident that the 27-year-old can fulfil this role.
"He played that lone striker and he played it very well. He's very fit.
"In forward areas we are limited but it's important that we work at it from midfield," Hessenthaler said.
With the new season less than a fortnight away, the former Dover boss said he was relishing the league campaign in his second spell in charge of the Gills.
"I'm excited. I'm a little bit apprehensive as all managers are. We need to make sure we get off to a good start this year," he said.
"As a manager and a coaching team we've been given every chance by what we've been able to bring in and what the chairman has done for us."
Source: BBC Sport
Source: BBC Sport