The good news: Florida State returns almost all of its defensive linemen. The bad: its two best players (Mario Edwards, Jr. and Eddie Goldman) are gone. Neither were the most consistent, but they were still clearly Florida State's best, and leave some large shoes to fill. The guys looking to fill in are either unproven or unspectacular.
We'll start with the proven but unspectacular.
Pretty solid seems like a good way to describe the interior duo of seniors Nile Lawrence-Stample (6'1, 310) and Derrick Mitchell (6'4, 303). You won't see many high up on draft boards, and they certainly are not difference makers, but if healthy, they can provide some solid play, keeping blockers off the linebackers and making some tackles for loss. But both have struggled to stay healthy throughout their careers. NLS tore his pectoral in the win over Clemson and managed to come back for the Rose Bowl after missing quite a bit of time. When he plays low and is in shape, he can be a valuable contributor. Mitchell had his first (mostly) healthy season after missing significant periods of time in previous years with various injuries. He uses his length to control blockers from the nose guard position, and could stand to get stronger in the lower body to better anchor.
But behind Lawrence-Stample and Mitchell are some defensive tackles with serious potential in sophomores Derrick Nnadi (6'2, 303) and Demarcus Christmas (6'3, 300). Nnadi was the more impressive of the two as a true freshman, showing good handwork and tremendous lower-body strength in limited action, including against Georgia Tech, stepping up with Goldman was lost to injury. Christmas is longer and profiles more as a penetrator. Jimbo Fisher claimed that he was as good as any defensive line recruit in the country, and while he did not make an impact reflecting that, he also wasn't a disappointment. Nnadi and Christmas have potential that Lawrence-Stample and Mitchell do not, they simply lack experience. In its attempt to replace Goldman on the interior, FSU needs health from the seniors and for the sophomores to step up. That starts in spring ball.
Then there are the wildcards on the interior: RSo. Keith Bryant (6'2, 319), RJr. Justin Shanks (6'2, 322), RSr. Giorgio Newberry (6'6, 285), RFr. Arthur Williams (6'5, 325), RFr. Adam Torres (6'4, 288), So. Rick Leonard (6'7, 270) and RFr. Fred Jones (6'2, 307). There are a ton of unknowns with this group that spring will help to sort out.
Quickly ... Bryant has ability but needs to show commitment to being a good player with better practice and work habits in what is now his third season. Shanks has never been able to stay healthy for an extended period, but has also not shown much when he didn't (outwardly) appear to be injured. Shanks recently posted on social media that he had dropped 20 pounds of fat and added 15 pounds of muscle and feels as good as he ever has, so perhaps there is hope for better production. Williams has tremendous potential, but came in extremely raw and very much needed his red-shirt season. Newberry has moved positions twice, from defensive end to tight end to defensive tackle and hasn't been able to catch on, though he, along with perhaps Torres and Leonard may be able to provide some help at the 5-tech position due to their length.
Note: FSU did sign the former No. 1 defensive end in the country in Josh Sweat, a five-star from Virginia who enrolled early. But he dislocated his knee and tore his ACL as a senior, and will miss spring as he rehabs. To the extent that Sweat will be on the field, he'll be able to take mental reps and see how college practices are run.
What about the pass rush?
Florida State's pass rush was not very good in 2014. There were a number of factors for this: underwhelming play by the defensive ends, suspect secondary play, not playing with huge leads like the previous year, injuries, etc.
A new ends coach is here in Brad Lawing, from Florida, after Sal Sunseri left to take a job with the Oakland Raiders.
Juniors Demarcus Walker (6'3, 277) and Chris Casher (6'4, 250) are back, a tandem that won't strike fear into the hearts of FSU's opponents based on past seasons, but that will give FSU experience and production in what looks like a rebuilding season. So far, Walker has been the far better of the two, being more assignment sound and showing more willingness to play the run. But he doesn't offer all that much as an outside rusher, whereas Casher could in theory, though he has not yet. If Casher stays healthy and shows better commitment, he could potentially give Florida State the pass rush it needs, as he certainly has the athleticism. But he also needs to increase his lower-body strength and be a more willing run defender.
There is youth and promise behind the pair, however, with sophomores Lorenzo Featherston (6'7, 220) and Jacob Pugh (6'4, 236), both of whom seem quite capable of playing the stand-up position when Florida State is in its 3-4 defense against 2-back or 2-tight personnel (FSU plays a 4-2-5 against 3 WR sets). Featherston showed great promise as a long, explosive pass rusher early on, but was exposed as undisciplined, unable to play the run, and then suffered injuries as the season wore on, none of which was unexpected for such a skinny freshman. He will need to add weight to be able to stay on the field on downs that aren't clearly passes, but did not look that much bigger in recent spring workouts 10 weeks after the Rose Bowl according to observers. His work on fundamentals this spring, and more importantly in the weight room this summer will have a big impact on this defense. Pugh does not have the length of Featherson, but is more versatile, being stronger against the run and able to cover down the field a bit better.
Florida State signed eight defensive line players in the 2014 class. Its 2015 defense will largely depend on how they develop. There is good reason to think it could be fantastic in 2016, but if it arrives a year early, as elite young talent sometimes does (see 2013 Seminoles like Jameis Winston, Jalen Ramsey, Mario Edwards, Jr., etc.), this defense might be better than expected. This is the group with the greatest potential for impact, as it has the most unknowns.