The Washington Redskins have pulled off a trade for the No. 2 overall pick in the NFL draft, sending three first-round picks and a second-round selection to the St. Louis Rams in a bid to draft Heisman trophy- winning quarterback Robert Griffin III, two people with knowledge of the situation said late Friday.

Redskins owner Daniel Snyder, known for big splashes during his tenure, authorized the blockbuster move even as the team’s hopes of signing free agent superstar Peyton Manning were fading Friday. The Redskins will send their first-round (sixth overall) and second-round picks in this year’s draft, plus first-round picks in 2013 and 2014, for what is expected to be the selection of Baylor’s Griffin.

The trade will not become official until Tuesday, which is the official start of the NFL’s 2012 calendar. Jay Glazer of Fox Sports first reported the news.

The Indianapolis Colts are widely expected to draft Stanford quarterback Andrew Luck first overall to succeed Manning, who was released by the team Wednesday. Friday’s trade would put the Redskins in position to select Griffin, a potential franchise quarterback.

The move is as risky as it is aggressive. By trading away four high draft picks in return for one, the Redskins are heavily mortgaging the team’s future to acquire Griffin, a rare but unproven talent, to lead the team in a league that increasingly belongs to a handful of elite quarterbacks.

Plagued by inconsistent quarterback play for the better part of 20 seasons, and with Coach Mike Shanahan needing to reverse his fortunes as he entered his third season in charge, the Redskins were not expected to move cautiously this offseason.

Last year, they passed on the chance to draft a quarterback, instead trading down from 10th overall to meet multiple roster needs by eventually acquiring 12 draft picks. But a year later, after a second consecutive season of double-digit losses, the team cast caution aside and went after Griffin, considered by coaches to be an electrifying quarterback capable of carrying the franchise for years to come.

Griffin, however, may need time to adjust to the NFL game. He ran a college-style spread offense at Baylor, winning the Heisman Trophy — the top award in college football — after passing for 4,293 yards, 37 touchdowns and only six interceptions. He also ran the 40 yard dash in 4.41 seconds at last month’s NFL Scouting Combine, speed that would make many wide receivers envious.

“This is the best throwing athlete I’ve seen come out in a while,” said former Baltimore Ravens coach Brian Billick, who now works for the NFL Network. “Far better than [Philadelphia Eagles quarterback] Michael Vick, in my opinion. Far better than [Carolina Panthers quarterback] Cam Newton.”

The Redskins had been in discussions with the Rams to acquire the No. 2 pick since the combine. The Rams, who already have third-year pro Sam Bradford at quarterback, sought to swap the pick for draft choices that would expedite their rebuilding process.

It was believed that the Rams would command a price similar to the one exacted by the San Diego Chargers in 2004, when they received two first-round picks, a third-round selection and a fifth-rounder from the New York Giants for Eli Manning, Peyton Manning’s younger brother.

But Washington gave up much more — an indication of team officials’ high opinion of Griffin, and of the pressure to turn the Redskins into winners. If Griffin is as good as advertised, he will ignite a struggling franchise and buy Shanahan more time.

“You’re not giving [those picks] away. You’re getting a quarterback who has star power,” ESPN draft analyst Mel Kiper said Thursday when asked about the price of moving up to acquire the Rams’ pick and the chance to draft Griffin. “I don’t care about the spots you move up. It’s a quarterback-driven league. Griffin is red-hot right now. . . . Dan Snyder knows what [the Redskins] need, and they’ve got to get a quarterback. They beat the Giants twice, and they beat Green Bay a year ago. He knows the missing link in Washington is quarterback.”

The Redskins and Cleveland Browns both wanted St. Louis’s pick, and Cleveland, which had the fourth and 22nd overall picks, was thought to have the upper hand. But Cleveland also had greater needs than the Redskins and apparently did not want surrender both its first-round choices this year.

Washington had aggressively pursued Manning following his release from the Colts. But as it became clear that Manning probably would end up elsewhere, the team turned its focus to the draft and pulled off the deal with the Rams.

More on the Redskins:

Mike Wise: The thrill of the gamble

Poll: What do you think of the trade?

Gallery: Robert Griffin III in photos

Redskins not on Peyton Manning’s itinerary

Latest Redskins updates on The Insider