Kirk Cousins came on in relief against Kansas City. (Ricky Carioti/The Washington Post)

For all the latest news today, click on this running Redskins story.

Updated 10:15, 10:50, 11:02 and 11:49 a.m.:

The Washington Redskins plan to start Kirk Cousins at quarterback Sunday at Atlanta, a move that would lead to them sitting down Robert Griffin III with three games left in his second NFL season, several people familiar with the situation said Wednesday.

Three of those people called Coach Mike Shanahan’s decision to start Cousins and sit down Griffin final. Two people familiar with the situation said it’s expected that Griffin will be deactivated for the remainder of the season, and that Rex Grossman will take over as the second-string quarterback.

Another person called Shanahan’s plan “tentative,” leaving open the possibility of reversing course. All spoke on the condition of anonymity because the Redskins had made no announcement. The team did not confirm that Cousins will start.

Shanahan said on Monday that if he did choose to replace Griffin with Cousins, that Griffin would not play for the rest of the season. And two sources said that the demotion includes the deactivation of the second-year quarterback.

Grossman hasn’t dressed for a game all season. Instead, the Redskins have gone with just two quarterbacks.

Three years ago, after Donovan McNabb fell out of favor with Shanahan, the coach not only benched McNabb, but also deactivated him while starting Grossman and elevating then-third-stringer John Beck to the No. 2 position.

Earlier this morning, Fox reported that Griffin will have a chance to make his case to Shanahan and potentially change Shanahan’s mind. The NFL Network reported that the Redskins have made a game plan with Cousins as the starter. ESPN reported that Cousins is to start.

Cousins would be making his second NFL start. He started and won a game at Cleveland late last season when Griffin, then a rookie, was hurt.

Shanahan said Monday that he was considering sitting down Griffin for the remainder of the season to protect the quarterback after he absorbed 24 sacks in the Redskins’ past five games.

Shanahan said then that if the move to Cousins were to be made this week, Griffin would not play for the remainder of the season. The Redskins are 3-10 entering the Atlanta game and have three games left.

Cousins took over for Griffin in the late stages of last Sunday’s 45-10 defeat to the Kansas City Chiefs at FedEx Field.

“I just prepare every game like I’m the starter, just so I have to be ready because I don’t want to get called into a game like this game and have not prepared the way I need to,” Cousins said after Sunday’s game. “So I’ll prepare the same as every week and do whatever I’m coached to do.”

A person familiar with the situation had said Wednesday that Redskins owner Daniel Snyder would not intervene in this week’s quarterback decision.

The move comes with Shanahan’s coaching tenure with the team likely coming to an end by soon after this season at the latest, according to multiple people familiar with the situation. ESPN reported Sunday that Shanahan contemplated quitting his job after last season because of dissatisfaction with the relationship between Griffin and Snyder. Members of the team’s management reacted angrily, according to people with knowledge of the matter, and wondered if Shanahan or someone close to him was responsible for those sentiments becoming public. The Redskins, people close to the situation have said, could consider trying to fire Shanahan for cause and attempting to withhold the remaining money due to him under the terms of his contract.

It is believed that Shanahan would receive the remaining money in his contract, which runs through next season and is worth about $7 million per year, if he is fired, barring a firing for cause, a maneuver that Shanahan could challenge via a grievance. It is thought that he would forfeit that money if he resigns.

Griffin, coming off knee surgery in January, has thrown 16 touchdown passes and 12 interceptions this season after throwing 20 touchdown passes with only five interceptions last season, when he was named the NFL’s offensive rookie of the year.

A person with ties to the organization said earlier this week that Shanahan’s threat to bench Griffin appeared aimed at trying to provoke Snyder to fire him immediately so that he could leave the organization with the money due to him under his contract.

Shanahan said Monday he needs to do what is best for the organization and he hopes Griffin understands that.

Mike Shanahan had been asked in recent weeks if he would sit Griffin and give Cousins a chance to showcase his skills and the coach said he would not because he believed it was necessary for the second-year quarterback to work his way through growing pains and play as much as possible after missing the offseason program. Some opposing players had said that they didn’t believe Griffin was healthy and that he shouldn’t be playing. Some members of the media also had opined that Shanahan should sit the struggling quarterback.

Asked about the notion of not playing the final stretch of the season, Griffin said last week, “I don’t take any offense to that. That’s just outsiders looking in that just don’t understand the game of football. When it comes to a time like this, it’s easy for guys to check out. I think it would be real cowardly of me to check out and say, ‘Hey, I don’t want to play these next four games.’ It’s not who I am. It’s not who any competitive football player is. You want to play, so we’re going to finish out the year and you take what’s happened this year, being 3-9, and you face it.”

What’s ahead:

●  Wednesday’s practice is at 11:50 p.m. Coach Mike Shanahan and quarterback Robert Griffin III are scheduled to meet with reporters after practice.

More from The Post:

Jenkins: Blinded by stars in Ashburn

Snyder won’t intervene in quarterback situation | QBs in limbo

Mailbag: Shanahan, Snyder and what’s to come | No resolution

Reid: Hire a true GM now | Hamilton: Problems start at the top

Wise: There’s one way Snyder can make Redskins fans happy

D.C. Sports Bog: 23 ways to force Snyder’s hand | Cooley on the mayhemMore

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Post Sports Live on Shanahan benching RGIII:

The Post Sports Live crew debates whether quarterback Robert Griffin III will be benched for the rest of the season and what would be Mike Shanahan's motivation in choosing to play Kirk Cousins instead. (Post Sports Live/The Washington Post)