Linebackers
Martrell Spaight (WAS): When given opportunity, Spaight has proven that he can produce. In a handful of games last season, he put up pretty nice stats. The Redskin defense is playing much better and even with the addition and great play of Zach Brown, Spaight's usage over the past two games has been increasing and his stats have jumped. A nice speculative add, as if Brown were to get hurt he'd be an every-week play. As it stands now you can plug him in and expect a handful of tackles, something that could prove useful in larger leagues.
Patrick Onwuasor (BAL): Kamalei Correa may still be the "starter", but Onwuasor is putting up better numbers. Double digits in two of the past three weeks doesn't scream mega-stud, but this spot has proven to be highly productive in the past so if you're in a larger league, or maybe even in a more shallow league where you don't necessarily have the best linebacking corps, this guy's worth an add.
Nicholas Morrow (OAK): With the state the Oakland Raiders linebacker situation is in, you take notice of just about every stat. Such as the UDFA rookie Morrow putting up at least one tackle in each game thus far in 2017. WLB starter Cory James has been fantastic (10 solos Week 4 against Denver) and then terrible (2 total tackles last week). If their season gets away from them, expect the Raiders to play the youngsters like Morrow. At worst a speculative add in larger formats just based on the fact that no one is particularly standing out at the productive linebacker spots for this team.
Others to Watch: James Burgess (CLE) and Jake Ryan (GBP)
Defensive Linemen
Christian Covington and Joel Heath (DE - HOU): With J.J. Watt shelved for the season, one of these guys will be given a big opportunity. It's likely Heath but Covington could figure into the mix. Heath was a pretty productive college player (Michigan St.) and is looked at more as a stopper than a game-changer like Watt, but in his first significant action logged his first sack of the season. Heath was an edge guy who bulked up and was going to move inside, Covington went the other way, going from an inside guy to more of an edge rusher. Neither will replicate half of what the "old Watt" brought but could prove worthy in deep leagues.
Vinny Curry (DE - PHI): Derek Barnett is apparently being brought along slowly which means Curry remains as a starter for now. He will never put up massive stats but against more statuesque signal callers there's at least a decent chance he can log a sack. Back in 2014, 9 of his 17 solo stops were sacks. Not saying he'll log 9 sacks this season but he's had 2 games with meaningful stats (in larger leagues) so the potential is there if you're really hurting at the position.
Others to Watch: David Irving (DT - DAL) and Darius Philon (DT - LAC)
Defensive Backs
Jalen Ramsey (CB - JAC): In shallower/smaller leagues that don't force you to start corners and safeties apart from one another, Ramsey could definitely be available. And he definitely shouldn't be. Ramsey is a mega-stud who is seeing more opportunities with A.J. Bouye playing well on the other side and their nickel corner also playing well. He was tested in 2016 and had 14 pass breakups. He's well on his way to outperforming that number and is also making more tackles. Get him on your team as the schedule is quite favorable and he stands to continue to produce.
Adrian Amos (S - CHI): Probably only a one-year add, as Quintin Demps return in '18, likely to a starting role. With Eddie Jackson penciled in on the other side, big plays could eventually be hard to come by but you gotta like what Amos has done in Demps' absence. Given what the Bears are working with, he should provide a steady source of consistent points based on tackles the rest of the way.
Andre Hal (S - HOU): The Texans' defense suffered a major blow this past weekend, losing two big-time playmakers and pass-rushers in J.J. Watt and Whitney Mercilus. This means the back end of the defense could potentially see more opportunities, both in terms of tackling and plays on the ball. Hal is getting a ton of snaps and is producing. Worth an add in larger formats for sure, and keep your eye on him in smaller leagues.
Others to Watch: Darian Thompson (S - NYG) and Dontae Johnson (CB - SFO)