Green took a puck to the head -- a Brooks Orpik shot to the ear -- in Sunday's 3-0 win over Pittsburgh.
"We're just being cautious," Capitals general manager George McPhee told ESPN.com via text Tuesday. "He won't play tonight. He will be fine for Saturday."
Green, who needed stitches, said after the game that he had a headache and felt woozy.
Capitals left wing Alexander Semin did return for Tuesday night's game against the San Jose Sharks, his first appearance since Jan. 8 as well as his first since signing a one-year, $6.7 million contract extension last month.
Semin had 18 goals and 17 assists at the time he was sidelined, but he hadn't scored since Nov. 28.
Pierre LeBrun covers the NHL for ESPN.com. Information from the Associated Press was used in this report.