Ropati Pitoitua (2015 Cap #: $2.125 million)
Pitoitua battled injuries in 2014 after signing a nice contract extension, tallying only 30 tackles and 2 sacks. He offers little in the way of a pass rusher, but he can set the edge against the run when needed, and is a valuable addition to a team that needs all the run stoppers it can get it's hands on.
Mike Martin (2015 Cap #: $680k)
The former 3rd round draft pick has 64 total tackles in 3 seasons, not exactly a glowing report. While he is an undersized lineman, he has plenty of strength and ability to play a penetrating role in the Titans 3-4 under Lebeau and Horton. Its fair to wonder whether he has plateaued in his development though. He's been rarely seen on game day since he arrived in Nahville.
The rookie defensive lineman was heavily talked up as a value pick for the Titans last year, but he spent most of the season on the inactive list, totaling only 8 tackles, a sack, and a forced fumble. The unit could use the run-stopping ability that he displayed at Penn State, and the Titans hope the 4th round pick can be more highly utilized in year two.
Sammie Hill (2015 Cap #: $3.8 million)
The so-called "MVP of the Defense" in 2014 is currently being investigated by Atlanta PD as part of a sexual assault case...so there's that. He was a big part of the Titans run-defense issues last season, and enters the last year of deal with a hefty $3.8 cap number, one that far outweighs his production. Last year Hill posted 33 tackles and 3 sacks, and while he will make a splash play on occasion, his propensity to being lost in the wash is not exactly ideal for Horton's 3-4 NT spot. I'm not 100% sure he's safe from becoming a roster cut, though the team's party line states otherwise.
Al Woods (2015 Cap #: $2.5 million)
Woods came to Nashville from Pittsburgh where he was being groomed to take over some additional responsibility on the line. In his first year in Tennessee he seldom played, posting 26 tackles and a sack. He was signed for a generous $2.5 million a year for two seasons, and may need to step up and help the Titans address their defensive line struggles.
Jurrell Casey (2015 Cap #: $4.5 million + signing bonus distribution = Ca $9 million)
The highest paid Tennessee Titans racked up 68 tackles and 5 sacks in 2014, with a significant drop off from 2013 sack totals. That said, he still played very well, posting excellent metrics against both the run and the pass. His new deal is an expensive one, but it's a contract the Titans can afford to pay (and needed to). Casey should be able to do some special things in the Horton/Lebeau system. The team will certainly lean on him going forward.
Karl Klug (Free Agent)
The only Titan defensive lineman free agent totaled 25 tackles and 2 sacks last year, and has been a rotational contributor since he was drafted. While he's undersized and will likely never be a starter, Klug is efficient with his limited time on the field, and seems to come up with plays more often than not. He should be available on the cheap for Tennessee, but no word yet on whether he is likely to return to Nashville or not.