The England forward has not played for the club since September 20 - initially missing with a groin problem before fracturing a toe.
Maresca told his pre-match press conference that Palmer was fit enough to play from the start in Sunday's match at Stamford Bridge.
A win for the second-placed Blues would lift them just three points behind the Gunners at the top of the Premier League.
"Everyone is happy, his teammates are happy, we are all happy and the most important thing is that Cole is happy because in the end football players want to play games," said the Chelsea boss.
Palmer, 23, was Chelsea's top scorer in the Premier League last season, with 15 goals.
He has made just four appearances in all competitions for the club this season, scoring twice.
"He is probably our best player," said Maresca. "We are happy that he is back. Now we need to give him time, you know, to be 100 percent fit.
"But he has done fantastic in the past and no doubt that he is going to do very good for this club in the future."
Brazilian wonderkid Estevao scored a stunning solo goal in Chelsea's 3-0 win against Barcelona in the Champions League on Tuesday, burnishing his reputation.
Maresca admitted pairing Palmer with Estevao, 18, was an exciting prospect.
"Depends against which team, depends a little bit on the game plan, but for sure the fans are excited to watch both together," he said.
"We also are excited, thinking that at the end we need always balance."
Maresca, who won the UEFA Conference League and Club World Cup last season in his first campaign at Chelsea, said his team had made progress over the past year but it was too soon to predict a title challenge.
"For sure it's different compared to one year ago, and it's because we spent one more year together," he said. "We went through moments where we can learn from that moment. Then again, for me it's very early.
"We are still at the end of November, December, so it's very early and it's important to be where we are now in March, April, and then we see."