"We still got some work to do," Franklin said in a teleconference.
The Lions return 11 seniors from its 2013 squad that went a wild 7-5, upsetting Wisconsin in the season finale and beating Michigan in four overtimes, but crumbling in defeat at Indiana and getting smacked by Ohio State.
The team averaged 28.7 points per game in O'Brien's offense led by quarterback Christian Hackenberg, the Big Ten Freshman of the Year.
Hackenberg, now a captain as a sophomore, threw for 20 touchdowns and 2,955 yards in his first year - 1,432 of which went to Robinson.
With Robinson gone to the NFL, Hackenberg won't have a clear No. 1 target to throw to, but a stable of pass catchers - both receivers and tight ends - might do the trick.
Sophomore wide receiver Geno Lewis, who caught two touchdown passes against Wisconsin, is the name on everyone's lips. Besides him, though, Penn State will be looking for production from untested freshmen wideouts.
Offensive coordinator John Donovan praised 6-7 junior Jesse James, who, along with 6-3 junior Kyle Carter, supplys Hackenberg with unmistakable targets at tight end.
"He's the prototypical guy you think of when you hear tight end," Donovan said of James. "He needs to be dominant."
Even with sophomore Adam Breneman lost for the season with an undisclosed injury, tight end is an area of depth and security for the Lions.
The same can't be said for the offensive line.
The Lions lost five senior starting or contributing offensive lineman from last season, and senior guard and captain Miles Dieffenbach suffered an ACL tear in the spring, so protection for Hackenberg isn't ideal.
Franklin said the Lions would utilize seven or eight players to fill gaps, even if it doesn't promote steadiness. The coaching staff doesn't really have a choice.
"Those players are going to have to be trained at multiple spots, which makes that consistency, that cohesiveness that you need at that unit difficult," Franklin said. "But that's really how we're going to do it."
The line will not only have to keep Hackenberg off the grass, but also open holes for senior running backs Bill Belton (803 yards, five touchdowns) and Zach Zwinak (989 yards, 12 touchdowns), who will both be depended on heavily in 2014.
If the Lions' line can do that, Franklin and his staff should feel rather confident given the relatively underrated defense they'll have this season. The defensive line is deep, and the secondary, led by junior cornerback Jordan Lucas and senior safety Adrian Amos, should hold up well.
Ironically, it could be Penn State's linebacker depth that could slow the defensive unit. Besides senior Mike Hull in the middle, questions marks abound throughout the unit.
Defensive coordinator Bob Shoop has ways to scheme around the depth concerns at linebacker, though; the most intriguing way would be using a "star" position or a 4-2-5 base defense. The coordinator said it would allow more flexibility defensively.
"That star position enables you to . . . play an outside linebacker there in certain situations, we can play a hybrid outside linebacker, strong safety," Shoop said. "We can play a corner there."
On special teams, Penn State returns senior Sam Ficken (15-of-23 field goals in 2013) as placekicker, three players are competing to replace punter Alex Butterworth who graduated.
Whether it's in the punting game, on the offensive line or at receiver, the Lions are still similar to virtually every college football team entering the season - they have their problems.
Only time will provide clarity into whether Penn State can overcome those shortcomings. That process starts with Central Florida on Saturday.
Penn State at a glance
Coach: James Franklin (first season, 9-4 with Vanderbilt in 2013)
Last year: 7-5, 4-4 Big Ten
On the web: www.gopsusports.com
Ticket info: 1-800-NITTANY
Worth watching: Despite some shaky games, Christian Hackenberg dazzled in the season finale with four touchdowns against Wisconsin. It could be a sign of things to come. Zach Zwinak and Bill Belton combined for 17 scores last season. Defensively, senior Mike Hull is well on his way to being the next star product of Linebacker U.
Great unknowns: How will the Nits replace the production and presence of offensive lineman Allen Robinson, who left for the NFL after his junior season? How quickly can this non-traditional line gel? With a larger focus on scoring and big plays, will Penn State's special teams explode or remain stagnant?
It all comes down to: Can Penn State win the games it's supposed to? If the Lions can get past Central Florida in the opener, there's no reason Franklin's team shouldn't be 5-0 heading into an Oct. 11 game at Michigan. But early success will depend a lot on the state of the offensive line.
Circle the dates: Penn State has three night games on the docket in 2014: Sept. 13 at Rutgers, Oct. 11 at Michigan and Oct. 25 at home against Ohio State. Rutgers, in its first Big Ten season, will want to win its conference opener, especially against the Lions. Playing Michigan and Ohio State will always draw interest, and the game against the Buckeyes will be a Whiteout at Beaver Stadium. With Ohio State quarterback Braxton Miller out with a shoulder injury, that game will be interesting.
Number crunching: Six of Penn State's 12 games last year were decided by seven points or less. The Lions held a 4-2 record in those games.
Prognosis: Depth concern at linebacker, trouble on the offensive line and unproven receiving options don't bode well for Penn State. But its 2014 schedule does. Escape Ireland with a win over UCF and favorable matchups early on against Akron, Rutgers, UMass and Northwestern, with games against Maryland, Temple and Illinois later in the year, makes the Lions' docket manageable. This won't be the best team Franklin will put out, but it could underwhelm and still win eight games. Hackenberg, if the line holds up, should actually grow as a complete passer with Robinson's absence. If Hackenberg can stand tall, so will the Lions.
On Twitter: @jmcgonigal9