INDIANAPOLIS – With plenty of focus on how the Packers might use free agency and the upcoming draft to improve their defense in 2017, Head Coach Mike McCarthy isn’t discounting another key piece to the process.

Last year at the NFL Scouting Combine, the Packers targeted four defensive players who turned into 2016 draft picks – defensive linemen Kenny Clark and Dean Lowry, and linebackers Kyler Fackrell and Blake Martinez – all of whom played as rookies.

Their progress in Year 2 could have as much impact on Green Bay’s upcoming season as any new acquisitions, a factor McCarthy remains fully in tune with as a draft-and-develop coach.

“Kenny, if you just watch the progression of the season, his arrow was straight up,” McCarthy said at this year’s combine of Clark, the Packers’ first-round pick in 2016. “I thought he played extremely well the last six weeks. That’s something we need to build off of.”

Clark’s game indeed went to another level late in the year. A key rotational player throughout the season, his impact plays increased down the stretch.

The 6-3, 314-pound former UCLA star recovered a fumble against the Vikings on Christmas Eve, batted down a pass in Detroit in Week 17, and led the defense with five QB pressures in three playoff contests. He also had a tackle for loss on a screen pass in Dallas. More than just the stats, Clark’s influence at the line of scrimmage stood out on film as well.

If Clark continues to develop a disruptive game similar to Mike Daniels’, the Packers will have a difficult tandem to handle on the interior up front in the defense’s primary nickel package.

“I think he’ll take that big jump as a second-year player,” McCarthy said. “It starts in the weight room.”

The weights will be the ticket for the other three as well.

Lowry’s game could expand with a full offseason of strength training. Mostly a five-technique end in 2016 – aligning head-up over the offensive tackle – the 6-6, 296-pound fourth-round pick from Northwestern could see more snaps inside in his second year, potentially rotating with Daniels and Clark.

“He came on at the end of the year,” McCarthy said of Lowry, who recorded his two sacks in back-to-back weeks in December. “Get another year of weightlifting, and he can play the one and the three (technique).”

McCarthy sees Fackrell, a third-round edge-rusher from Utah State, with a “good frame” (6-5, 245) suited for “10-12 pounds of lean muscle mass” this offseason. His biggest rookie highlight was a strip-sack of Giants QB Eli Manning in Week 5.

Crediting Fackrell for coming a long way on special teams as a rookie (he ended up tied for second on the team with nine coverage tackles), McCarthy wondered if he was headed for a strong finish like Clark had it not been for a late November hamstring injury that cost him three games.

“If he doesn’t get hurt he probably would have played a ton more,” McCarthy said. “He was playing really well when he got that hamstring.”

Martinez, a fourth-round inside linebacker from Stanford, also missed three late-season games due to injury (knee).

Early on, though, he earned the starting job to open the year and took on communication responsibilities in the huddle, a credit to a young player. After the knee injury, his snaps on defense were reduced as Joe Thomas assumed more of an every-down role.

All of it, the ups and downs, provided experience Martinez (6-2, 237) can learn from as he seeks out and competes for his role on defense moving forward, whatever it may be.

“I think all these guys that fight through injuries, particularly when they’re young, early in their career, it needs to be evaluated and make sure they’re preparing themselves to get through that phase,” McCarthy said.