Redshirt freshmen are becoming less common as more players contribute straight out of high school. They still can have an impact, though.

That's particularly true on the offensive and defensive lines, where players regularly need that extra year to gain the physical strength necessary for the college game.

Southern California defensive tackle Jay Tufele has shown this summer how much he's benefited from that time in the gym.

Tufele arrived on campus as the nation's No. 3 defensive tackle and No. 39 overall prospect in his class, according to composite rankings of recruiting sites compiled by 247Sports . One year later, he's a likely starter who should play a vital role on USC's defense.

USC coach Clay Helton said last weekend Tufele has had "the best camp of anybody."

Some other redshirt freshmen who could make a major impact this season:

NOTRE DAME WR/RB JAFAR ARMSTRONG

Notre Dame technically doesn't label any of its players as redshirt freshmen, but Armstrong fits the profile as a sophomore who didn't play a down last season. Armstrong signed with Notre Dame as a receiver but started working more in the backfield this spring and has impressed. Notre Dame coach Brian Kelly has cited Armstrong's versatility while comparing him to Theo Riddick, a former Irish running back now with the Detroit Lions. Armstrong could get a featured role in a Notre Dame rushing attack that's unsettled following the departure of Josh Adams and the dismissals of CJ Holmes and Deon McIntosh .

PITTSBURGH CB PARIS FORD

Ford could end up contributing for the Panthers in a variety of ways. Although Ford figures to make his biggest contributions in the secondary, he also could emerge as one of Pitt's top return men and may even make some cameos on offense. Ford scored 22 touchdowns in five different ways — runs from scrimmage, receptions, interception returns, punt returns and fumble returns — while starring for Steel Valley High School in Pittsburgh.

MARYLAND QB KASIM HILL

Hill played three games last year and went 18 of 21 for 230 yards with no interceptions before tearing his anterior cruciate ligament and sitting out the rest of the season . Hill is back and competing for the starting spot with sophomore Tyrell Pigrome, who also tore his ACL last season. Other Big Ten redshirt freshman quarterbacks competing for starting spots include Minnesota's Tanner Morgan and Nebraska's Tristan Gebbia.

FLORIDA STATE WR TAMORRION TERRY

Whether Deondre Francois or James Blackman wins Florida State's quarterback competition, the Seminoles could use more playmaking receivers. Florida State's top returning receiver is Nyqwan Murray, who has been working his way back from a knee injury that occurred in spring practice . Terry's impressive performance in preseason camp suggests he could fill a need and emerge as one of Florida State's top weapons. Terry had 129 yards receiving and a touchdown in Florida State's spring game.

LOUISVILLE RB COLIN WILSON

Louisville's offense could focus more on the running backs now that 2016 Heisman Trophy-winning quarterback Lamar Jackson has moved on to the NFL's Baltimore Ravens . That could put more of a spotlight on Wilson as he attempts to make a triumphant return from a torn ACL. Wilson rushed for 69 yards on six carries in three games last season before getting hurt, enabling him to take a medical redshirt.

GEORGIA OT ISAIAH WILSON

Wilson has been working with Georgia's first-team offense at right tackle for much of preseason camp as the Bulldogs attempt to replace New England Patriots first-round draft pick Isaiah Wynn , who was the starting left tackle last season. Andrew Thomas, the starting right tackle last season, has moved over to the left side this year. Wilson was rated as the nation's No. 16 overall prospect in his high school class according to the 247SportsComposite.

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EXTRA POINT

Six more redshirt freshmen who could make an impact this season:

— Justin Broiles, S, Oklahoma

— Terrell Cooper, DL, TCU

— Abraham Lucas, OT, Washington State

— Scott Nelson, S, Wisconsin

— Randall St. Felix, WR, South Florida

— Austin Williams, WR, Mississippi State

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AP Sports Writer Gary Graves and freelance writer Steven Bittenbender in Louisville, Kentucky, contributed to this report.

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