"I remember freshman year, I hated pass-blocking with a passion," he said. "Now it's something I love doing. It's something that gets me going even before I run the ball. You have to have the right mindset for it."

Williams' game is by no means perfect in that area, but a good example of his attitude toward it came in last week's preseason game vs. Pittsburgh. One play after having his ankle twisted in the pile by a Steelers linebacker, Williams had to pick up a blitzer off the edge and steered him well clear of QB Brett Hundley. Then he exited the game.

Of the Packers' three draft picks at running back a year ago, Williams was the most advanced as a pass protector, but the progress he's made since then hasn't gone unnoticed, either.

"Getting into the intricacies of any offense, and with Aaron (Rodgers) as our quarterback we have more … our backs are really stressed," McCarthy said. "We put a lot on those guys, and it's a real credit to him he has picked it up and excelled the way he has."

He's proven to be an effective pass-catcher out of the backfield, too, despite limited opportunities at BYU. Last season, Williams' 54-yard touchdown on a screen pass at Pittsburgh and a 30-yard TD reception at Cleveland dwarfed anything he'd done as a receiver since his freshman year.

Those big plays, which contributed to 25 receptions for 262 yards on the season, happened for a simple reason, according to Williams.

"People not thinking I could catch," he said. "They just don't think I can be an impact in the passing game, so they leave me open, leave me with a linebacker, stuff like that, and you have to take those advantages.

"If they don't think you can do it, show them wrong."

Williams began the 2018 preseason with an 8-yard touchdown reception against Tennessee, making a tackler miss in the open field before diving across the goal line.

That could be a sign of the next thing on his prove-it list – elusiveness, which could produce some longer runs for the ground game. Of Williams' 153 carries as a rookie (for 556 yards), only one went for 15-plus, yet he knows he's capable of more.

A back doesn't average 5.7 and 5.9 yards in his sophomore and senior years in college, respectively, as Williams did without breaking his share of long ones. That's where the intricacies of the offense McCarthy referenced come into play.

"I could have had a lot more explosive plays last year if I really just kept my eyes up and knew what type of run it was, have more detail about our running plays," Williams said.

"Last year, I knew where I was going and I just followed my blockers. This year it's more of, I know where I'm going, I know where the blocks are, what type of defense they're in, and who's going to go where. So I feel I've got more of the details this year."

If that's indeed the case, the Packers' offense will surely benefit. The aforementioned ankle injury only kept Williams out of practice for a couple of days, so whether or not he plays much the rest of the preseason, Week 1 does not appear to be in jeopardy.

Offensive coordinator Joe Philbin praised Williams' versatile skill set, sounding excited about all the different ways the Packers can use him and noting "you don't have to necessarily pigeonhole him."

Because you almost can't, and that gives NFL defenses plenty to pay attention to when it comes to Williams' game.