When Zach Collins first stepped foot into the Trail Blazers’ practice facility as a rookie last summer, the 7-footer said he weighed 220 pounds.

To his teammates, he became “The Big Skinny” – a respectful, but playful jibe on his lanky build.

One year later, the talk about Collins around the team has changed.

“I call him Big Z,’’ Wade Baldwin said. “Everybody calls him Big Skinny, but I like to boost his confidence and call him Big Z.’’

It’s not just a ploy to boost confidence, though. There’s more than a little bit of truth to a Big Z moniker.

Collins today says he is consistently registering 240 pounds on the scale, meaning he has put on 20 pounds since his rookie season. He says he arrived in Portland at 220, started last season at 228, then got as high as 234.

“I've put on 5-to-7 pounds since the end of the season. It’s crazy, yeah,’’ Collins said. “It’s crazy.’’

Of all the to-do items for the Blazers’ future, Collins adding size and strength was chief among them. Throughout a solid rookie season, when he averaged 4.4 points and 3.3 rebounds in 16 minutes, talk of Collins was usually couched by that faraway date when he would add size.

But after an accelerated summer regimen, the future appears to be now, as evidenced by what has become a pronounced chest and thicker arms.

“Everything is just a little bit more solid,’’ Collins said. “I just know I feel stronger in everything I do.’’

He knew he would be able to put on weight, in part because he says he has always loved the weight room because it eliminates outside elements.

On the court, he has to think about guarding his man, helping teammates on defense, making the right passes and having the correct shooting form. But in the weight room, it’s just him and the weights.

“I like the simplicity of that; it’s all about how hard you want to work,’’ Collins said.

His new body will be on display at the Las Vegas Summer League, where the Blazers begin play Saturday against Utah. Collins, who broke his nose colliding with teammate Caleb Swanigan in Tuesday’s practice, will be wearing a plastic mask during the games.

His improved frame couldn’t have come at a better time for the Blazers, a point that was driven home by a chance encounter with Neil Olshey, the team’s top executive.

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The day after the Blazers were swept by New Orleans, Collins said Olshey and the coaching staff noted that they envisioned him becoming more of an interior post man next season.

Collins said he went home to Las Vegas and took about three weeks off. When he returned to the practice facility for his return to training, he ran into Olshey outside the team’s locker room.

“Neil stopped me outside the locker room and told me he wanted to get me playing with my back to the basket more,’’ Collins said. “That he wanted me to get my game more inside-out.’’

For Collins, it was music to his ears.

“That’s how I’ve been playing all my life,’’ he said. “Last year was a little bit of a different role.’’

Last year, he played mostly alongside Ed Davis, and Collins would work on the perimeter while Davis set picks and dove toward the basket. Nearly half of his shots last season were from 16 feet and beyond.

“I think getting a rhythm closer to the basket and being able to see the ball go in a little bit more, rather than coming into the game and having to fire up perimeter shots will be good for me,’’ Collins said. “I’m comfortable doing that and looking forward to that being more a part of my game this year.’’

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To be effective inside in today’s NBA game, you have to be strong and explosive.

For as much toughness Collins showed last season – a factor that earned him unwavering respect from the veterans – he did have a tendency to lose the ball on contact, or get pushed out of position.

And that’s where the Blazers’ five-day-a-week weight lifting program has come into play. It’s not just dumbbells and bench presses, but more core strengthening, explosion drills and balance work.

“It’s all about lifting the right way,’’ Collins said. “Especially nowadays. Everybody is so athletic, everybody is so strong and explosive. Especially for big guys. There’s not a lot of back-to-the-basket bigs, but they are still out there. There are still bigs who can overpower you.’’

Collins, though, says his weight lifting is not just to hold his ground. He found last season that absorbing contact against stronger opponents took a toll on his body.

“That’s one reason why the weight room is important – to stay healthy,’’ Collins said. “If you are light, you can bang as much as you want, but you are going to break down, just because you aren’t strong enough.’’

Today, teammates chuckle when they think of the gangly rookie from last year. They joke that Collins is now all about tank tops and short sleeves that show off his muscles.

Collins, though, says his body isn’t the only thing improved. For the first time in two years, he will be returning to the same team. From Bishop Gorman High in Las Vegas to Gonzaga to Portland, he has felt like he’s been caught in a whirlwind of change.

Now, as his body changes, his mind can rest easier.

“I tell people all the time that I’m really excited for next year because the last two years I’ve had to learn everything on the go,’’ Collins said. “From being a freshman at GU to being a rookie here. Now I get to come back and I kind of know what to expect. I can already feel it in Summer League. Like, I already know what spots to go to, where I want the ball. So, I’m excited for that.’’