Four pounds might not sound like a lot, but the change is an obvious one for Green Bay Packers running back Ty Montgomery.

Now 220 pounds, or four pounds heavier than his listed playing weight from last season, Montgomery looks jacked up and ready to inflict punishment as he transitions into his second season at running back.

Here’s a good look at a more muscled Montgomery – who is still rocking the No. 88 – from Tuesday’s open OTA session in Green Bay:

Ty Montgomery is seriously jacked. pic.twitter.com/2s2Gn1ZFz1 — Zach Kruse (@zachkruse2) May 23, 2017

Montgomery has always been a thick, muscular player, especially for a receiver. Left tackle David Bakhtiari said last year that the receiver-turned-running back looks like an “Under Armour model,” with “muscles on muscles,” but Montgomery now appears better built to handle the snap-to-snap violence of the running back position.

He also has a better handling of how to play the position. Thrown into the fire by necessity midway through last season, Montgomery often thrived on nothing more than natural ability – but now he’s ready to take the next step as a runner.

“I was running on a lot of instincts when I ran the football,” Montgomery said, according to Ryan Wood of PackersNews.com. “I knew where I was supposed to be going, but it was instincts. Now, I know techniques, I know rotations and linebacker positions and fronts and understanding gap rules and what the defense is supposed to be doing. Now I get out there, I know my reads and my aiming points. I can just add that to my instincts, and I’m excited to do that.”

Coach Mike McCarthy and the Packers talk every offseason about the “second-year jump,” or the development so often seen as rookies transition into their second seasons. Montgomery might be a third-year NFL player, but he could fit the description – especially when you consider he’s been a running back for less than a full year and he played in only six games as a rookie in 2015.

In fact, Montgomery said he felt like last year was his rookie season:

Ty Montgomery on RB: "I’m going into my third year, but it feels like I’m going into my second year, coming off my rookie year" #Packers — Wes Hodkiewicz (@WesHod) May 23, 2017

The on-the-job training continues for Montgomery, who now leads a running back filled with five rookies. Still, working every day with running backs coach Ben Sirmans should only help him grow, according to offensive coordinator Edgar Bennett.

“You have an opportunity to get in that room full-time, day in and day out, it certainly helps from an environment standpoint understanding his assignments and how to apply his fundamentals and techniques,” Bennett said Tuesday. “Anytime you have an opportunity to have that experience, it only helps you as you grow and move forward.”

Protected by muscle and increasingly more confident in his new job responsibilities, Montgomery has clearly put in the work – both physically and mentally – to prepare for his first full season as the Packers top running back.