By Paul Vozzella
NEFJ Correspondent

Before the start of free agency, the interior defensive line was one of the weakest position groups for the Patriots.

Not anymore.

New England swooped in and signed Milton Williams to anchor the front line and Christian Barmore seems ready to roll, but there’s no certainty he will be able to return to his former self in full. With Mike Vrabel now at the helm, how much he values loading up the trenches for the future is going to play a big factor in  whether or not the team adds more depth at the position.

Here are some of the best that could be available:

Mason Graham, 6’3.5 296, Michigan

The Good: Great pass rush from the interior. Profiles as a great three-technique but will have situational versatility. Generates enough power to throw offensive linemen off-balance and create separation. Good IQ. Quick hands. High motor causes consistent disruption. Tracks down ball-carriers and tackles well.

The Bad: Awkward build with short arms. Will have to rework pass rush repertoire to play to strengths; swim move will not be effective with short arms. Inconsistent against double teams; can get overpowered. Tendency to overcommit to pass rush and lose gap integrity.

Final Thoughts: Graham’s athleticism for an IDL is impressive. The speed-to-power is clear and, despite his less-than-ideal frame, makes him a problem that will need to be schemed against. His pass rush consisted of some moves that will have a hard time translating because of his short arms but his run defense is a plus.

Omarr Norman-Lott, 6’2 291, Tennessee

The Good: Burst at snap is elite. Athleticism is off the charts. Relentless pass rush. Speed to power. Good blend of physicality and finesse. Good against the run. Shows ability to hold gap against run and fights down blocks. Keeps eyes in the backfield while engaged in blocks. Good pursuit.

The Bad: Endurance concerns due to low snap count. Inconsistent pad level. Leans on athletic ability over technique. Will allow ball-carriers to run out of tackles. Did not display enough against the run to prove he can be responsible for two gaps. Snaps on tape where he is digested by blocks.

Final Thoughts: The ceiling is as high as any other IDL in the draft. The former Arizona State DT showed signs of promise against the pass and run. Tennessee often rotated IDLs, leaving his endurance as a concern. When Norman-Lott was on the field for extended time, he showed signs of fatigue. Nonetheless, you will get a 100% effort from him. He is a pure three-technique.

Derrick Harmon, 6’4.5 313, Oregon

The Good: Drops anchor and does exceptional at holding ground one-on-one and against double teams. Reads blocks. Maximizes 34.5” arms with hand placement to gain control of blocker. Gets skinny to break through zone blocks. Good motor. Athletic pass rush. Can play one or three-tech. Scheme versatile.

The Bad: Inconsistent play. Doesn’t have deep bag of pass rush moves. Plays with high pad level at times. Great frame but needs to get lighter up top and more stout in lower half.

Final Thoughts: The tape shows flashes of a first-round talent. He doesn’t seem to be in the best shape and it’s evident in his inconsistent pad level and all-out effort. Reshaping his prototypical frame can turn Harmon into a well-known DT. He has the ability to be a very good run stopper as well as a guy who creates pressure in the backfield.

Alfred Collins, 6’6 332, Texas

The Good: Prototypical frame for IDL. Good hand and anchor fundamentals at snap. Possesses enough agility to take advantage of poor technical blockers. Has great habit of disrupting passes with raising arms. Good swim move in pass rush. Can take on double teams. Engulfs ball-carriers on tackle attempts.

The Bad: Lacks quick burst. No pursuit skills and will not be a factor on outside plays. Questions about being in-shape. Stiff laterally. High pad level on pass rush. Does not have versatile pass rush repertoire. Lethargic footwork

Final Thoughts: Collins has something you cant teach: size. He has the talent to be a great rotational piece right away with the chance to develop into a really good three-down threat. His energy dissipates quickly. If he can become more lean, he will maximize his potential. Collins strikes me as a one-tech with upside as a three-tech.

Darius Alexander, 6’4 305, Toledo

The Good: Great schematic and alignment versatility. Active hands from snap to whistle. Holds his gap and can find success as a two-gap DT. Reads RBs well. Strength to outpress linemen. Good combo of agility, quickness and power. Several solid pass rush moves. Possesses power and finesse.

The Bad: Old age raises concern about room for growth. Lacks quickness and lower half fundamentals. Tendency to play with higher pad level. Endurance concerns. Relies on athleticism oftentimes. Will not track down ball-carriers.

Final Thoughts: After flying under the radar at Toledo as a dependable run-stopper, Alexander proved he has a terrific skill set against the pass at the Senior Bowl. He will be 25 years old at the beginning of the regular season, old enough to take a draft stock hit. Alexander may be the most versatile IDL this year and is a very intriguing prospect.

Shemar Turner, 6’3 290, Texas A&M

The Good: Terrific hands. Consistently sheds blocks. Scheme versatility with alignment experience from zero-technique to five-technique. High energy, tenacity and violence. Powerful punch and quickness paired with technique translates to success in the pass and run game.

The Bad: A little light for the interior. Does not do well against double teams. Plays with higher pad level that will lead to allowing extra yards vs. RB. Limited pass rush moves. Lack of counter moves.

Final Thoughts: While he is a well-rounded player, Turner does not excel in many aspects of the game. He is a bit of a tweener at his size and will probably need to bulk up and commit to playing the interior. He is best suited as a three-technique. His ceiling is as a reliable three-down lineman with the floor as a rotational interior rusher.

CJ West, 6’1 316, Indiana

The Good: High intelligent player. Able to read blocks quickly and beat blockers to spots. Holds his gap against outside zone schemes. Good motor throughout play. Good endurance for IDL. Shows ability to sneak through double teams.

The Bad: Loses wide base due to turning shoulders and/or narrowing feet. Less-than-ideal burst in first two steps. High pad level at times. Limited to one-gap run responsibility. Smaller tackle without technique to make up for it.

Final Thoughts: Shows flashes of really good play. West needs a lot of work on his technique and some basic fundamentals. He is a high-effort player that can stay on the field for some time without a major decline in energy. He will strictly play inside and possibly just as a zero or one-technique.

Ty Robinson, 6’5 288, Nebraska

The Good: Ideal frame for the position. Interesting combo of athleticism and IQ. Identifies plays quickly. Super explosive. Plays with tenacity. Power creates separation. Plays at a surprisingly low level for size.

The Bad: Noticeably short arms limits pass rush ability and dependable tackling. Doesn’t move well laterally because of stiff hips. Gets eaten up on down blocks. Doesn’t have great gap integrity against the run. Clear refinement needed in technique.

Final Thoughts: Robinson shows promise to be a really good rotational DT. His lack of fundamentals against the run and short arms limit his ceiling. His high motor and imposing power will draw the attention of many coaches, and he presumably has a wide-ranging rank on big boards.

Jamaree Caldwell, 6’2 332, Oregon

The Good: Terrific run stopper. Bench presses opponents and moves well laterally. Low pad level and anchor allows him to eat double teams. Fundamentally sound footwork. Does a good job reading the backfield. Classic one-tech or nose tackle.

The Bad: Offers next to nothing in pass rush game. No evident pass rush moves. Not quick enough to rely on natural talent as a rusher. Hand placement needs improvement. Can get lost in traffic. Inconsistent tackling.

Final Thoughts: Caldwell is a one-dimensional one-technique run stopper. He will only see the field on first and second down, or obvious run situations. His pad level, power and ability to read the backfield make him a two-gap DT. If Caldwell can become a better tackler, he will have a long, successful career as a professional.

Joshua Farmer, 6’3 305, Florida State

The Good: Another high-energy defensive lineman. Quick. High-end athleticism displayed on stunts and one-on-one pass rush. Good pass rush with a lot of room for growth. Exceptionally long arms. Two-gap potential.

The Bad: Struggles against run; borderline liability at times. Trouble detaching from blocks. Gets washed away against zone blocking. Inconsistent pad level. Bad habit of letting energy up when play is going to the opposite side of the field.

Final Thoughts: Farmer needs a lot of coaching-up to have a successful career but possesses a lot of the natural gifts coaches look for in a defensive lineman. Farmer can turn into one of the best pass-rushing IDLs in the league but his run defense is bad enough to keep him off the field. Mid-level ceiling with very low floor.