NASHVILLE, Tenn. -- A look at what's happening around the New York Jets:

1. Growing pains: Sam Darnold's return to the lineup, whether this week or next, will be the big story for the final month of the season. He was struggling before his foot injury, so it will be interesting to see how (if?) he improves over the final few games. Like a lot of young quarterbacks, he's having a hard time with zone defenses.

Darnold torched one zone-based defense, the Indianapolis Colts, but he hasn't been able to find that magic against other teams. One AFC personnel director said the Chicago Bears "caused problems" for Darnold by dropping eight into coverage at times.

A zone is difficult for a young quarterback because the defenders are facing him, reading his eyes. It also can be hard to diagnose the specific type of coverage. Defensive coordinators can be diabolically clever. With man-to-man, what you see is what you get. The Tennessee Titans, it should be noted, are primarily a "man" defense that relies on blitzing.

In college, the coverages are vanilla because defenses want to keep it simple against no-huddle, hurry-up offenses. In the NFL, the coverages are sophisticated.

"Yeah, definitely, I'm seeing some different things every single week and it's a little bit harder than college," Darnold said. "But at the same time, I'm learning really fast and [I'm] very optimistic of where I'm going and where this team is going."

2. Read 'em and weep: Bad teams produce ugly statistics, and the Jets have a few whoppers:

• No takeaways in five straight games. This is a franchise record and it's tied for the longest streak in NFL history (since the 1970 merger). The Jets' most recent takeaway was a fourth-quarter interception by Darron Lee against the Colts in Week 6. Since then, they've gone 337 defensive plays without one. Leaguewide, there have been 202 turnovers in that span (six weeks, counting the Jets' bye).

• Only five touchdowns in the past five games. Eight players across the league have scored more touchdowns than the Jets over the past six weeks. No, the Jets aren't generating a lot of fantasy points.

• Two straight 200-yard rushing days by the opponent. The last time that happened to the Jets was early in the 2002 season, when they surrendered three in a row. Remarkably, that team rebounded and won the AFC East -- their most recent division title, by the way.

• Five straight games with less than 100 rushing yards. The last time that happened within the same season was 2005, when Curtis Martin broke down near the end of the season and the Jets were left with Cedric Houston at running back.

3. Leo's lament: This has been another frustrating year for Leonard Williams, who has been sitting on three sacks for six games. Before the season, he talked about becoming a better fourth-quarter player by improving his technique and conditioning. Well, after 11 games, he's still looking for his first fourth-quarter sack. Granted, the Jets have been playing from behind, reducing pass-rushing opportunities, but his overall production hasn't been great.

"Well, obviously, the stats aren't where we want them to be right now," defensive line coach Robert Nunn said. "He's had a lot of bad luck the last couple of years, but that's no excuse. We need him to be more productive and I've got to put him in positions to be more productive."

Williams needs to be paired with an edge-rushing threat, but that simply isn't the case on this team. As a result he gets double-teamed, although Nunn made it clear that's not an alibi.

"When you're a player with his talent, that's what's going to happen," Nunn said. "We have to coach around those situations."

Williams is signed through 2019 at $14.2 million. At this point, the Jets might want to wait before re-upping, especially if there's a new coaching staff.

4. Not in Kansas anymore: One of the more puzzling lineup decisions involves rookie Nathan Shepherd, who has started every game at defensive end even though he hasn't produced (15 tackles, zero sacks). Look, I get it, the Jets are trying to develop a raw player from a small school (Fort Hays State), but what kind of message does that send?

Nunn admitted Shepherd's performance last week was "the worst outing he's had," so it will be interesting to see if the coaching staff makes any adjustments. Shepherd, a third-round pick, has more upside than Henry Anderson, but Anderson is a better player right now. Shepherd has played 262 defensive snaps to Anderson's 422, but the fact that he gets 24 snaps per game is a clear example of how player development, in some cases, is prioritized more than a meritocracy.

5. Remember the Titans: Sunday would've been a juicy revenge game for wide receiver Rishard Matthews, who had a messy breakup with the Titans in September, but it's hard to seek redemption when you're not playing. Matthews, who has no catches and has played only 42 snaps in three games with the Jets, expects to be inactive for the second consecutive game. It has been a frustrating few weeks for Matthews, who signed Oct. 23 when the team was banged up at receiver.

"It's not what I had in mind," he told ESPN. "They had their guys before I got here and I understand that. When I first got here, I thought I'd be involved more. Now those guys are back healthy and it is what it is."

Matthews doesn't play special teams, which hurts his cause. At the same time, we're talking about a player with 118 receptions and 13 touchdowns in the previous two seasons. The 29-year-old believes there's a lot of good football left in him, but he might not get a chance to prove it this season.

"Maybe I'd be a little more hyped [about Sunday] if I was involved more," Matthews said, "but that's not the case."

6. Film school: Two unusual plays from last week's game sparked a lot of chatter in the film rooms. First, there was Josh McCown's "helicopter" run for a first down, a la John Elway. Players marveled at McCown's all-out, sacrifice-the-body effort. Darnold, inactive for the game, was standing next to backup Davis Webb on the sideline when it happened. He said Webb was so sure that McCown would come out of the game that he buckled his chin strap. McCown stayed in.

The other play was Cordarrelle Patterson's crotch grab on Anderson, which gained traction on social media. As I understand it, it drew a lot of laughs in the film room. Two veterans told me they'd never seen anything like that before in an NFL game.