The Chicago Bears have received major contributions from a few members of the rookie class through the first quarter of the season. However, not everyone in the class has thrived so far.

Unlike last season, their biggest contributors have come on the defensive side of the ball. Their offensive additions have made a minimal impact.

It's still early to make an accurate assessment of how their careers will go with only four games in the books. We have a pretty good idea where their respective rookie seasons are going at this point, though.

Dillon Thieneman: Neutral.. but very high

Dillon Thieneman squarely belongs in the Defensive Rookie of the Year conversation right now. He's had at least six tackles in every game, and Sunday's win over the Jets marked the first game in which he didn't have a pass deflection (the fact that the defense was only on the field for 32 plays and the Jets called only 15 passes surely played a role there).

You could make a strong case that he's been Chicago's best defensive player thus far, and that's saying a lot when his running mate, Coby Bryant, has been on IR since the start of training camp. Thieneman has had an awful lot on his plate, and he's thrived anyway.

Logan Jones: Falling

Logan Jones really might not see the field this season. Aside from a terrible performance against Minnesota in Week 2, Garrett Bradbury has held his own at center.

The veteran would have to lose the job for Jones to crack the lineup. The odds of that happening don't seem high after he's stacked solid performances against the Eagles and Jets. Fans will lament this selection at the end of the season, but he's a shoo-in to take over the starting job next offseason, with Bradbury only playing out a one-year deal.

Sam Roush: Neutral.. but very low

Speaking of draft picks that Bears fans lament, Ben Johnson doesn't seem ready to give up on the Sam Roush experiment anytime soon. The rookie tight end was on the field for 23 plays against the Jets. Unfortunately, he just can't seem to get out of his own way.

Sure, Roush got into the stat sheet with an 8-yard grab against the Jets. However, that 8-yard grab was a screen pass that could've been an explosive play if he waited for the convoy of blockers he ran around. He really might've reached the end zone from 30 yards out if the blockers did their job downfield.

Is he potentially being overanalyzed because of a rough showing against the Vikings? Sure. Any other player would get the same treatment if they got tackled short of the first-down line after running around their blockers on a screen play, though.

Zavion Thomas: Falling

Zavion Thomas saw a career-high 9 offensive snaps against New York. Why is his stock down? Because Ben Johnson isn't scheming passes his way. He didn't have a single target against a team that is severely lacking speed at cornerback.

Notably, Thomas has also been somewhat disappointing in the return game after showing a lot of promise there in the preseason finale against Tennessee. He gained only 70 yards off 4 kick return attempts against the Jets. An average of 17.5 yards per return won't cut it for someone who was drafted in the third round largely for the impact he'd bring to the return game.

Their decision not to use Thomas on punt returns is also a conundrum, especially considering Kalif Raymond's impact on offense thus far. Has he shown ball security issues there in practice? Or do they just like what they've seen from the veteran there?

Malik Muhammad II: Rising

Malik Muhammad II has been a revelation. The fourth-round pick has already settled in as a key defensive starter, and defensive coordinator Dennis Allen has already said that he might be their best cover man. He's earned that praise, too.

Muhammad has allowed only 8 catches on 18 targets and has given up a passer rating of 41.9% when targeted. The 22-year-old is coming off another rock-solid performance against the Jets, and he helped the team hold Garrett Wilson to only three grabs for 27 yards. Muhammad might not be a household name yet, but he certainly seems well on his way.

Keyshaun Elliott: Falling

On the bright side, we don't have to keep using Keyshaun Elliott's Arizona unis. They FINALLY snapped a picture of him. However, that picture was taken on the sideline.

He's only played on special teams thus far, and is still waiting to see his first action on the defensive side of the ball. Unfortunately for him (and fortunately for everyone else), with the starting linebackers settling in nicely after a rough start to the season, he'll probably have to keep waiting. It always seemed like a redshirt year for Elliott after he missed virtually all of training camp.

Jordan van den Berg: Neutral

The Bears' defense only played 32 defensive snaps against the New York Jets. The fact that Jordan van den Berg played seven of them shows they've seen enough from him to give him a spot in the rotation. It's not like anyone on the defensive side of the ball was gassed at any point and he needed to come in to relieve them.

However, JVDB still played the second-fewest snaps among all nine active defensive linemen, behind only special teams ace Daniel Hardy, who has only seen seven snaps on defense this season. The rookie defensive tackle's role could expand as the season progresses, but he'll have to make the most of the limited opportunities he receives. He hasn't done so thus far.