GREEN BAY – The third and final day of the NFL Draft isn't typically known for finding immediate Year 1 starters and impact players.

But that's what happened last spring when the Packers drafted Minnesota linebacker Kamal Martin in the fifth round and signed UCLA's Krys Barnes as an undrafted free agent.

The two rookies climbed Green Bay's depth chart at inside linebacker and wound up seeing significant playing time in the heart of the defense.

Barnes came out of nowhere to wear the communication helmet during the second half of the year. Despite playing only the 12th-most snaps on defense, Barnes finished second on the team with 78 tackles, leading all NFL undrafted rookies in 2020.

Martin used a fearless playstyle to make a serious run at capturing a starting job in training camp before suffering a knee injury in the final week of August that would sideline him for the first five weeks of the regular season.

The 6-foot-3, 245-pounder returned in October and eventually settled in as the "Will" linebacker in the Packers' base defense, racking up 24 tackles and a sack in 190 snaps over 10 games.

While the Packers didn't add any veterans to the group this offseason, the young makeup of the inside linebacker room has Green Bay excited about its future.

"This whole group got some experience last year because a lot of guys had to play," inside linebackers coach Kirk Olivadotti said. "Now obviously we want to take that experience and build on that and try to make it where we're getting better at one thing at a time. If you look at everything that we did, we did some good things, and we got some stuff to improve."

The Packers originally went into 2020 with the expectation veteran Christian Kirksey would replace Blake Martinez as the every-down "Mike" linebacker on defense.

However, a chest injury to Kirksey pushed those responsibilities to Barnes, a well-regarded team captain at UCLA whose draft stock was hurt by the cancellation of the school's pro day due to the COVID-19 pandemic.

Despite not having the benefit of a physical offseason program, Barnes put together a strong camp and earned a spot on the Packers' roster after Martin was placed on injured reserve to start the regular season.

"He's obviously a guy that has made plays when he's gotten in in the game," said Olivadotti last season. "He works extremely hard, communicates well, can play ahead of plays. He's still a rookie in a lot of ways, and he is a mature rookie. … The even temperament he has, through good plays and bad plays, he has a pretty even pulse all the time."

Barnes also had to scale a few mountains of his own on the injury front. In addition to spending most of November on the COVID-19 list, the 6-foot-2, 229-pound linebacker played through calf, shoulder and biceps injuries during his 13 regular-season appearances.

He also started the NFC Championship Game against Tampa Bay after breaking his thumb a week earlier against the Los Angeles Rams.

There stands to be competition for all the key inside linebacker posts this summer, but the one guaranteed place where the Packers will need to find a replacement is Kirksey's spot in nickel.

Martin did some of that last year. Returning third-year veteran Ty Summers also has played there, though he spent most of last season as the backup to Barnes in the "Mike" role.

The other option is fourth-year veteran Oren Burks, who is back with the inside linebackers after briefly moving outside midway through last season.

The former third-round pick has been a stalwart on special teams over the past three seasons but has played just 275 defensive snaps due to untimely injuries and limited opportunity.

"We just decided that would be the best spot for him to learn the defense through," said Olivadotti of Burks. "O.B. is just outstanding as far as learning the defense. He's great on the practice field, he's always going to be the guy that's running around and is really good for the group to have in there. So, it's really nice to have him back in the room with us."

Rookie sixth-round pick Isaiah McDuffie also could factor into the competition after finishing his run at Boston College as the fourth-leading tackler in the NCAA Division I Football Bowl Subdivision.

As a linebacker coach by trade, new defensive coordinator Joe Barry is pleased with the pieces he has to work with during his maiden voyage in Green Bay – from the returning veterans down to the incoming McDuffie.

"He is a guy that plays extremely hard," said Barry of McDuffie. "I've been impressed with the way that he works. All you have to do is click on the film and you see there's a guy that's going to play extremely hard all the time.

"He fits in with this group very well because that's what this group is – a bunch of guys that, they're going to work at it, they're going to play hard."