GAINESVILLE (CBSMiami) – If you’re a head coach hoping to get a good shot in on a weakened Southeastern Conference defense, you better hope you get your shot in this year.

That’s because defenses across the SEC are having to rely on underclassmen after the NFL draft decimated most of the defenses in the conference.

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Thirteen of the 20 SEC players selected in the first two rounds of this year’s draft were defensive studs. Now, almost every contender in the SEC has at least one defensive starter just out of high school.

The youngsters are learning on the job, and the lessons have been difficult.

“When guys get thrown into the fire right away, we’re watching them mature right before our eyes, and it’s painful sometimes,” Georgia coach Mark Richt said. “They just have to keep their faith and keep banging away, so they can keep getting better.”

Georgia has had five freshman defenders start games this season and the seventh-ranked Bulldogs are allowing a league-worst 32.2 points per game.

No. 9 Texas A&M has played 17 true freshmen overall, tied with UCLA for the most of any Football Bowl Subdivision school. Georgia and Tennessee have each used 14. Top-ranked Alabama and No. 10 LSU have played 13 apiece.

“That’s part of the SEC,” Tennessee coach Butch Jones said. “You’re going to attract the best of the best. We try to recruit individuals who as true freshmen can play right away and play early.”

It’s not unusual for a freshman on offense to spark an SEC’s title run – running back T.J. Yeldon and receiver Amari Cooper were two of the top playmakers on Alabama’s national championship team last year.

Defensive players, however, often need more time to develop.

“I think it’s tough in this league, but there are many (freshmen) that are doing it right now and some are having great success,” Mississippi coach Hugh Freeze said. “The easiest position (on defense) to teach would be defensive line, but that doesn’t mean it’s easy to play there with some of the offensive linemen we come up against. But that would be the easiest mentally to learn. And then the hardest is the secondary, unless you’re just going to play some base coverages and not get too far out on things.”

Experienced QBs around the conference have taken advantage of inexperienced defenses, but several young defensive backs have been able to hold their own.

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Florida cornerback Vernon Hargreaves heads the list. He is tied for the SEC lead with three interceptions and hasn’t allowed a touchdown pass for the 17th-ranked Gators.

“We’ll play freshmen when they’re ready, and this guy’s ready,” Florida coach Will Muschamp said. “That’s the bottom line.”

Other starting cornerbacks in the SEC include LSU’s Tre’Davious White, Alabama’s Eddie Jackson and Tennessee’s Cam Sutton. Alex Sezer started each of Texas A&M’s first two games. Safeties Tray Matthews and Quincy Mauger and cornerbacks Brendan Langley and Shaq Wiggins have started for Georgia. Mississippi’s Tony Conner and Kentucky’s Blake McClain are starters at nickel.

Freshmen also are making an impact in the front seven.

Georgia’s Leonard Floyd has a team-high 10 quarterback hurries and is tied for the team lead with three sacks. Tennessee’s Corey Vereen applied the pressure that led to a game-clinching interception in a recent 31-24 triumph over South Alabama. Texas A&M linebacker Darian Claiborne has topped his team in tackles in two games. Montravius Adams leads Auburn with six hurries, while teammate Carl Lawson produced two sacks Saturday in a 30-22 victory over Mississippi.

“It means a lot,” Lawson said after his big performance, “but there are still a lot of things I can go back and fix.”

Indeed, all these freshmen have much to learn. For example, Vereen recorded a sack during Tennessee’s second-half comeback in a 34-31 overtime loss to Georgia last week, then committed a personal foul on the Bulldogs’ game-tying touchdown drive.

With so many freshmen, SEC teams are winning with offense, not defense.

Florida and Alabama are the only SEC schools ranked among the top 25 teams in total defense or scoring defense.

For everyone else in the conference, they hope their freshmen grow up quickly.

“When you learn, you make mistakes,” Richt said. “It’s just the way it is. You hope they can learn and make mistakes while they’re in practice, as they’re getting their chance to start two or three years in, but that’s not the way life goes all the time.”

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(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)