Maybe it’s time to check and see if Pac-12 basketballs are still regulation size.

Either they’ve gotten smaller, the rims have gotten bigger or the players have had Lasik surgery, en masse, because long-range shooting has taken a major step up  in the conference.

Consider: A year after no team shot better than Arizona’s 37.1 percent from behind the arc, five teams are above that level for three-point shooting.

Oregon State has shot nearly 41 percent from outside; UCLA, 40.5 percent. The league’s fifth-best outside-shooting team, Oregon, is shooting 38.2 percent from three-point range, with a pair of veteran transfers leading the way. Last year, Washington State ranked fifth at 34.7 percent.

Two years ago, it was largely the same, with Stanford leading the way at 37.9 percent, and only woeful Utah and USC in the dregs at 30.6 percent and 27.1 percent, respectively. Some things never really change — the Trojans are still horrendous at 29.4 percent — but with NCAA-wide offensive rules opening up the game for penetrators and creative coaches, teams are shooting less from the perimeter and making more.

“There are a lot more fouls being called, so that’s encouraged a number of guys who would settle for a three to drive more to get to the line,” Oregon coach Dana Altman said. “Some of our games have been called like they were a year ago, some really close. The officials are still trying to figure out how to call games. It’s been a change for players, coaches and really officials.”

Part of it also could be considered youthful ignorance.

Three of the conference’s most efficient outside shooters are true freshmen: leader Hallice Cooke of Oregon State, at a Pac-12 best 54.8 percent three-point shooting, and UCLA’s duo of Bryce Alford and Zach LaVine, at 42.5 percent and 42.2 percent, respectively.

Alford is the son of Bruins head coach Steve Alford — one of the best shooters in NCAA history during his time at Indiana — so maybe you can expect that. LaVine also was considered one of the top prospects in the country entering this season.

But Cooke was an unranked three-star out of New Jersey’s St. Anthony High, and his production has been staggering, especially with teams hunkering down on the conference’s leading scorer Roberto Nelson, who ranks seventh in three-point percentage (41.1 percent) and fifth in three-pointers made per game (1.92).

“Hallice has just turned out to be such a wonderful surprise,” Oregon State head coach Craig Robinson said. “We thought he’d be good, just not this good, this soon. He’s given us another outside threat to go along with Roberto, and now that teams are keying on Roberto, Hallice has been able to open up his game offensively.”

In the case of the UCLA sharpshooting duo, getting to learn under the elder Alford has paid immediate dividends, particularly with practice structure.

“We don’t do a lot of free shooting,” Alford said. “Most of our shooing is done game-speed and with shots we’d get within our offense. Those are the shots we like to take. There’s usually always a coach involved — I’ve always believed shooting has to be done at full pace because that’s how it happens in games.”

It’s not just the youngsters who are having all the fun outside. Recess has been called for the Pac-12’s elder statesmen, as well.

Washington’s C.J. Wilcox, who leads the conference with 2.88 threes per game after ranking fourth and second during his sophomore and junior years, respectively, is back up near 40 percent after dropping down to 36.6 percent three-point shooting last year. Huskies head coach Lorenzo Romar hesitates to credit the rule change; rather, he just thinks Wilcox return to 100 percent health has him streaking.

And then there’s Oregon’s deadly duo of Jason Calliste and Joseph Young, a pair of transfers who have instantly become two of the Ducks’ outside options.

Calliste ranks second in the Pac-12 at 51.2 percent three-point shooting after making just 36.5 percent last season for Detroit, and sixth in the conference at 1.83 threes per game. Young, who transferred from Houston, ranks eighth at 40.8 percent.

“They’ve done a great job for us — Joe really is lighting up here lately, and Jason’s numbers are really good for the season and for the conference,” Altman said. “He’s been really consistent. Those two guys have been a lot of fun to work with, added a lot to our scoring.”