If Doughty wins, he will become the second-youngest in league history to receive the Norris Trophy. Bobby Orr was 20 years, three months when he won the first of his record eight Norris Trophy titles. Doughty turns 21 in early December.
"It's pretty cool," Doughty said. "Bobby Orr is obviously one of the best defensemen to ever play the game. To be close to doing the same thing he did, it's kind of surprising. It's very humbling and it's a pretty big honor, as well."
"He said congrats, and I said, 'For what?'" Doughty said. "I didn't know they were announcing the finalists today. So he told me, and right away I called my dad to look up the NHL's site to see if it was true, and it was."
"His year has been spectacular through this season," Kings coach Terry Murray said. "He's an anchor for us back there."
Keith, 26, had career highs in goals (14), assists (55) and points (69), and was a workhorse, playing in all 82 regular-season games for the third time in five years in the NHL.
"I think he's had a special year," Hawks coach Joel Quenneville said. "He's one of those players you have to admire how he competes. His quickness, agility, anticipation and thought process defensively evolved and continued to get better and improved in his career.
"Offensively, he rose his game to another level. He had the puck a lot, helped our power play, helped our special teams, influenced us in our puck-possession game. He was complete in all aspects. Look at his numbers and the way he played, and I think he's very deserving."
Green, 24, was a Norris Trophy finalist last season and the runner-up to Boston's Zdeno Chara. He led all defensemen this season in goals (19), points (76), assists (57) and power-play goals (10).
"The [offensive numbers] are nice but not something where I can hang my hat and feel like I've accomplished something," Green said to NHL.com. "I think there's a lot more to accomplish. The thing is, I am looked upon to score goals and create offense from the back end. But I'm trying to become a complete player -- that's what I'm striving for."
The winner will be announced June 23 during the NHL awards show in Las Vegas.
ESPNLosAngeles.com's Arash Markazi and The Associated Press contributed to this report.