GREEN BAY - His rookie season wasn't even over and Aaron Jones already knew where he needed to take a step in Year 2.

The Packers running back made significant contributions last year after being selected in the fifth round out of UTEP, twice earning a pair of NFC Rookie of the Week honors for 100-yard rushing performances against Dallas and New Orleans.

As soon as the momentum started to build, however, a pair of knee injuries sidelined Jones for three combined games and limited him to only 19 carries after Green Bay's Week 8 bye.

A review of his rookie season revealed Jones needed to further develop the lower half of his body to stand up to the wear-and-tear of an NFL season and improve his skills in pass protection.

So when Jones wasn't busy earning his college degree this offseason or helping grandmothers navigate the Appleton International Airport, the second-year running back was a steady presence in the weight room.

Once Jones returned for the start of the offseason program in April, the emphasis was obvious on the practice field.

"I'm bigger all around," Jones said. "That's something that's going to help me in pass protection and that's something I want to get better at. I'm stronger, so definitely when a defender who's bigger than me comes up I can hold my ground this year."

Pass protection is a crucial component for Green Bay running backs blocking for two-time MVP quarterback Aaron Rodgers. It's also the surest way to stay on the field with the Packers' preference to stay in a no-huddle mode of offensive operation.

While Jones is thicker in his lower body, neither he nor position coach Ben Sirmans feel the 5-foot-9, 208-pound running back has lost any of the explosiveness that allowed Jones to average of 5.5 yards per carry on 81 attempts last season.

Jones rushed for nearly 300 yards in a three-week stretch from Oct. 8 to Oct. 22 before injuring his knee against Chicago in Week 10. He missed two games, but returned in December.

When it looked like Jones was getting back into a rhythm with three carries for 47 yards against Carolina, he then injured his other knee against Minnesota on Dec. 23 and sat out the season finale against Detroit.

"It was really frustrating," Jones said. "I feel like it kind of messed up the season I was having, but I was still there for my teammates and still enjoyed being here. I came back from one and then injured the other one, and that was even more frustrating.

"I was like, 'How unlucky am I,' but I was lucky at the same time because it could have been ACL. MCLs you just have to rest."

The silver lining for Jones was his knee injuries would not require surgery, allowing the 23-year-old running back to jump right into his offseason routine.

While some injuries cannot be avoided, Jones hopes the byproduct of his increased strength will help him avoid more preventable soft-tissue injuries.

Sirmans agrees Jones' biggest area to work on this offseason was developing more lower-body strength. When the season was over, the Packers' running backs coach even put together a tape showing Jones how a little more strength will help his overall finish.

Sirmans cautions the true impact of Jones' offseason might not be seen until the pads come on in training camp, but he is fully convinced Jones did everything possible to prepare his body for the long haul.

"Over time, you start getting that grown-man weight, which is good weight," Sirmans said. "When you see a guy come in as a rookie - in all sports - by the time they get to their third or fourth year, you can see how their body has changed, just naturally, now that you're in more of a system that's really focusing on your body and what you're putting in nutritionally and how you're working out."

The Packers' backfield competition could very well be the most highly contested position battle in training camp with Jones, Jamaal Williams and Ty Montgomery all having proved they can handle starting responsibilities when summoned into action.

If recent history is any indication, the two more sure-fire ways for a running back to earn playing time are through durability and accountability.

After emerging as one of the league's most explosive young runners last season, Jones hopes the improvements he made this offseason will result in him becoming the complete running back he knows he's capable of being.

"I feel like any athlete wants to get bigger, stronger as long as they can stay explosive," Jones said. "I still feel just as explosive as I was, if not even more."