Christian Hackenberg and Cardale Jones were once considered first-round NFL talents. After struggling with accuracy and pocket presence in their junior seasons, both players slid down NFL draft boards and are expected to be selected outside the top 32 picks.

Why were Hackenberg and Jones originally projected as top-tier prospects and what are the concerning characteristics holding each of these players out of first-round projections?

• Gruden's QB Camp, 8:30 p.m. ET, Tuesday on ESPN

Christian Hackenberg

After an up-and-down college career, Hackenberg enters the draft as one of the most polarizing prospects in 2016. As the top-rated quarterback prospect in the 2013 ESPN 300, Hackenberg started all 38 games for Penn State from 2013 through 2015 (21-17 record) and earned Big Ten Freshman of the Year honors in 2013 under then head coach Bill O’Brien.

After O’Brien left to join the Texans before the 2014 season, however, Hackenberg struggled with his accuracy (54.8 completion percentage), efficiency (43 Total QBR) and sack avoidance (FBS-high 82 sacks) in the past two seasons.

Greatest strength: size

Despite his recent struggles, Hackenberg is still considered a second- or third-round prospect because he checks all the boxes of a prototypical NFL quarterback. At 6-foot-4, 223 pounds, Hackenberg has ideal size for the position and a strong arm to make all the throws.

Despite enduring more sacks than any other college player in the past three seasons (103), Hackenberg never missed a start at Penn State and was one of the most durable quarterbacks in the country.

Greatest weakness: accuracy

Hackenberg completed a career-low 54 percent of his passes in 2015, which ranked 96th out of 114 qualified quarterbacks.

Taking it a step further, Hackenberg’s standardized completion percentage, which adjusts for pass distance and eliminates drops and throwaways, was sixth worst of any Power 5 quarterback and significantly lower than any other top-10 quarterback prospect this season.

Over the past four seasons, no FBS player selected in the first three rounds of the draft had a standardized completion percentage lower than 67 percent in his final college season. Even after removing all pass attempts in which Hackenberg was under pressure, his standardized completion percentage does not surpass 63 percent.

Cardale Jones

Jones was thrust into the spotlight at the end of the 2014 season after J.T. Barrett went down with an injury. In three starts for the Buckeyes, Jones led Ohio State to a Big Ten championship and national championship in the postseason.

After a hard-fought battle with Barrett last spring, Jones was named Ohio State’s starting quarterback for the 2015 season. But his inconsistency and inaccuracy lost him the job midway through the season despite his never losing a game in his college career.

Greatest strength: arm strength

Jones showcased his strong arm in Ohio State’s run through the 2014 postseason. In those three games he completed 8 of 14 passes thrown 25 yards or longer with four touchdowns and zero interceptions.

At times Jones forced the deep ball in 2015, but his arm strength is undeniable as he completed nearly 73 percent of his passes longer than 10 yards and to the sidelines last season.

Greatest weakness: decision-making

In the NFL, quarterbacks make their money on third down and in the red zone. Jones struggled mightily in both areas last season.

On third down Jones converted a first down on 31 percent of his dropbacks and posted a QBR of 26. Jones was off target on nearly 18 percent of his third-down attempts and, when he did complete a third-down pass, it was short of the sticks nearly 42 percent of the time.

Jones also completed less than 36 percent of his passes in the red zone and posted a 28 QBR within the 20-yard line. He had as many sacks as touchdown passes in the red zone (two).

Hackenberg and Jones had different paths to the draft but both are defined by their physical tools and relative inaccuracy in college. Find out what Jon Gruden thinks of these strong-armed prospects on Gruden QB Camp Tuesday at 8:30 p.m. ET on ESPN.