Advocaat, who arrived at Sunderland on March 17, guided the squad to Premier League safety with just match of the campaign remaining.
The Dutchman has confirmed he will mull over the offer of a three-year contract and make a swift decision.
And Fletcher, who ended his six-month goal drought in Sunday???s 3-1 defeat to Chelsea at Stamford Bridge, reckons the former Netherlands boss is the right man for the job.
“If he does stay, that would be great for us next year,” Fletcher told the Sunderland Echo.
“He’s a hero with the Sunderland fans for keeping us up.
“We’ve reacted to him because he’s given us the belief. He’s brought the best out of us.”
Regardless of Advocaat???s decision, Fletcher expects plenty of changes at the club over the summer.
“There will be a lot happening in the summer,” Fletcher said.
“There’ll be a lot of people leaving too, so it will be interesting to see what happens.”
Before his goal against the champions, Fletcher last scored on November 3 against Crystal Palace, but he was just relieved to get back on the scoresheet on what was always going to be a difficult match for Sunderland.
“It’s been a while, so it was good to get on the scoresheet,??? Fletcher said.
“We knew going there that it was going to be hard with them winning the league.
“They keep the ball for fun, and they’re nice to watch, even when you’re playing against them. But I thought we put in a good performance.”