The U.S. international will return for the 2013 season after an extended break, according to the Galaxy head coach
Donovan, 30, spoke openly of his mental exhaustion leading up to and directly following the Galaxy's 2012 MLS Cup triumph, even publicly toying with retirement.
But Arena, who spoke to Donovan on Sunday, has said the U.S. international will play a role in the 2013 season.
“We've given him a little bit more time off,” Arena said. “He's definitely playing this year, just working out a return date that makes sense for all of us.
“We haven't narrowed it down yet. We'll wait and see. We haven't firmly established a return date yet.
“I thought he was going to come back, I think he just needs an extended leave of absence. He's had a couple years that have taken its toll.”
Donovan is one of 12 Galaxy first-team players who skipped the first day of pre-season, including Todd Dunivant - who is on his honeymoon.
And Arena said he was happy to tailor pre-season training for some of his older players.
“[Donovan], like any player, needs the right time of pre-season to get ready to play. The longer he takes off, it's going to take him a longer period of time to be ready to play,” Arena said.
“The older players, they prefer less time [in pre-season] because it wears them down. The younger players can deal with the grind a little bit better.
"But generally we like to see players get three to four weeks in before they're ready to play. Then you need some real competitive matches to bring your fitness along.”
Donovan's absence has also ruled him out of the January U.S. training camp and contention for the World Cup qualifying match against Honduras on February 6, according to U.S. coach Jurgen Klinsmann.