(John McDonnell/The Washington Post)

Rex Grossman and Pat White are both scheduled to play at quarterback for the Washington Redskins in Monday night’s preseason game against the Pittsburgh Steelers at FedEx Field after fill-in starter Kirk Cousins exits.

Cousins is scheduled to play about a half. Coach Mike Shanahan said the precise amount of playing time that Grossman and White receive will be determined as the game progresses.

“Rex will get some playing time and Pat will get some playing time but… a lot is determined by the number of plays,” Shanahan said Friday at training camp in Richmond. “You’re guessing there because you’re not sure the time of possession. Even last week with our defense, we put some guys in early in the fourth quarter and they got five plays apiece. So you are never really sure how many plays they get. But it’ll be somewhere in the area that hopefully we can split out the reps.”

Shanahan has continued to say that he will withhold Robert Griffin III from the entire preseason as the Redskins’ starter at quarterback works his way back from knee surgery in January.

Have a Redskins question? E-mail Mike Jones at mike.jones@washpost.com with the subject line “Mailbag question” for him to answer it in The Mailbag.

What’s ahead:

● Washington hosts the Pittsburgh Steelers Monday at 8 p.m. in their first game of the preseason at FedEx Field.

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