Their first four draft picks were designed to help the struggling defense, but the Green Bay Packers got their biggest rookie impact from two of the three running backs they selected on the final day.

Here's a breakdown of the Packers' 2017 draft class:

Grade: Below average.

Best rookie: Fourth-round pick Jamaal Williams was the workhorse running back, while fifth-rounder Aaron Jones provided the explosive change. Williams led the Packers in both carries (153) and rushing yards (556), but his average of 3.6 yards per carry suggests he's more of a plodder. He also might be the more capable back in the passing game, both as a receiver and a blocker. Jones, despite a pair of knee injuries, showed more big-play ability. He averaged 5.5 yards per carry on just 81 attempts (448 yards) and matched Williams with four touchdowns, including the game winner in overtime against Tampa Bay to help the Packers stay alive in the playoff race at the time. Both had at least one 100-yard rushing game, and this duo looks more promising than opening-day starter Ty Montgomery as the future of the Packers' backfield.

Most improved rookie: This one has to go to an undrafted rookie, punter Justin Vogel. He looked shaky in training camp but progressed as the season went along. He set the franchise record for net punting average (41.6), although a relatively mild weather season at home helped. Still, this spot should be solidified for next season.

Most disappointing rookie: Throughout the offseason practices, Josh Jones was seemingly around the ball at every turn. But the second-round pick couldn't carry that over when it mattered. He bounced between safety and inside linebacker in the Packers' nitro package, but other than the overtime interception in Cleveland that set up the game-winning score, he struggled in coverage most of the season. This was a classic case of a player who looked good in helmets and shorts but struggled when the pads came on. Top pick Kevin King also could be thrown into this category, but as cornerbacks coach Joe Whitt said during the season, no one saw the real King because when he played, he was limited by a shoulder injury that eventually ended his season and required surgery.

Jury is still out on ...: Montravius Adams and Vince Biegel. Both missed the early part of the season because of injuries. Adams, the third-round defensive tackle, broke his foot during the opening week of training camp and played in only one of the first seven games. Biegel, the fourth-round outside linebacker, had foot surgery in May and missed the entire offseason, training camp, the preseason and the first seven games of the regular season. The Packers hoped Adams would bolster their run defense and Biegel would provide some pass rush. Neither happened.

Undrafted rookie evaluation: The most promising undrafted rookie didn't even see the field until Week 16. Receiver Michael Clark, a 6-foot-6 former college basketball player, caught four passes for 41 yards in the final two games combined. Yes, he struggled with drops, but his length and athletic ability make him a player to watch next summer after he has had a full year to refine his skills. Cornerback Lenzy Pipkins also looks like he might have potential.