Oregon quarterback Marcus Mariota (8) has announced he will return for the 2014 season. (Ezra Shaw/Getty Images)

Earlier this fall, when the Ducks were undefeated and quarterback Marcus Mariota had emerged as the Heisman Trophy frontrunner, it appeared that the Oregon star was on his way toward a top selection in the 2014 NFL draft. However, following the team's recent losses to Stanford (26-20 on Nov. 7) and Arizona (42-16 on Nov. 13) -- and with Mariota's production falling off a bit, some of which can be attributed to a lingering injury in his left knee -- the signal-caller has announced he's returning to school for his junior season.

From the official Oregon release:

“It is an honor to be a student at the University of Oregon and to have the opportunity to represent our institution on the football field alongside my teammates,” said Mariota. “I look forward to earning my degree next year and to the rest of my career at this great University.”

Mariota exploded on the national scene during his redshirt sophomore campaign, throwing for 3,412 yards with 30 touchdowns and four interceptions and rushing for 582 yards and nine scores. He adjusted quickly to the departure of Chip Kelly and the elevation of former offensive coordinator and current head coach Mark Helfrich.

The Ducks had lofty BCS aspirations this season, and falling short of the BCS and Pac-12 championships likely had something to do with Mariota's decision to return. Depending on which other players stick around, Oregon's offense could be more potent than ever in 2014 -- wide receiver Bralon Addison and running backs Byron Marshall, De'Anthony Thomas and Thomas Tyner are all eligible to return.

Center Hroniss Grasu's choice to come back to Eugene is also extremely significant. The 6-foot-3, 297-pounder made SI.com's midseason All-America team and is widely regarded as one of the top offensive linemen in the country. He is a contender for this year's Rimington Trophy.

“The University of Oregon is a special place and I’m extremely happy to be returning for my senior year,” Grasu said. “To be a student-athlete in this community is an honor and an experience I’ll continue to cherish with my teammates.”

Had Mariota and Grasu opted to declare for the draft, the balance of power in the Pac-12 might have shifted away from Oregon. The Ducks came into 2013 having played in four straight BCS bowls, thereby establishing the program as a West Coast powerhouse. But given Stanford's rise as perennial BCS contender, Arizona State's breakthrough under Todd Graham, UCLA's improvement beneath Jim Mora Jr. and USC's recent hire of Steve Sarkisian, Oregon could have taken a step back with the loss of its premier playmaker and anchor of its line.

That said, Mariota's decision to return is a risky proposition. While a similar choice seems to have worked out for Louisville's Teddy Bridgewater and Clemson's Tajh Boyd (and Stanford's Andrew Luck when he came back for his junior campaign in 2011), others, such as USC's Matt Barkley and Washington's Jake Locker, have seen their draft stock decline. Particularly given Mariota's build (6-4, 211 pounds) and style of play, he could be susceptible to injury. However, if he's able to continue to improve, he has the potential to be the first quarterback taken in the 2015 draft (should he declare after his redshirt junior year).

Earlier this fall, Fox Sports' Joel Klatt caught up with Mariota, where the quarterback talked about becoming more vocal and his growth as a player.