Looking at the first 48 hours of the new NBA season, I saw plenty of great power forwards in action.

They just happened to be all the guys who played small forward last year.

One of the ongoing trends in the NBA has been toward “smallball” lineups that feature four perimeter players and a single big man, and judging by the first two days of action it appears the trend has only gained steam.

The Phoenix Suns pioneered the approach two years ago under coach Mike D’Antoni, and their success has spawned countless imitators. Helping the process along, of course, have been the new rules restricting defensive contact on the perimeter, shifting the balance of the game from big plodders like Shaquille O’Neal and Tim Duncan to quick guards like Dwyane Wade and Kobe Bryant.

You didn’t have to look far for a good example. Over in the Meadowlands, the Nets’ primary power forward on opening night wasn’t Nenad Krstic or Jason Collins — it was Bostjan Nachbar. He played 25 minutes (all of them at the power forward spot) and scored 14 points in New Jersey’s 102–92 win over Toronto.

The Nets were comfortable with that arrangement partly because Toronto used 6-foot-7-inch Morris Peterson as its power forward for half the game, hoping to shoot quickly and pile up the points with a frenetic pace. (They succeeding on the first count, taking 94 shots, but not the second — they hit only 39.4%).

The Knicks went a bit more traditional in their marathon opening game against Memphis, but not much. Quentin Richardson played the power forward spot in spurts, as did Renaldo Balkman, joining a smallball perimeter quintet of Steve Francis, Stephon Marbury and Jamal Crawford. For its part, Memphis countered with slender rookie Rudy Gay playing “power” forward for a good chunk of the evening.

The trend of the two local teams was mirrored throughout the league. Whereas smallball used to be a “look” teams would throw in for five minutes or so to catch an opponent off balance, it’s now increasingly the “base” lineup that teams use. Now, going big is the oddball variation.

Witness some of the starting lineups we saw on opening day. Golden State shifted a scrawny 6-foot-9-inch wing, Mike Dunleavy, to power forward and moved Jersey boy Troy Murphy to the middle. Boston took it a step further, moving 6-foot-7-inch jump-shooter Wally Szczerbiak to that position and backing him up with 6-foot-7-inch Ryan Gomes. Even traditionalists like Houston coach Jeff Van Gundy are going in this direction, using Shane Battier as his power forward after Battier had been a small forward for five years in Memphis.

As a result, the league is trending ever smaller. Phoenix, the originator of the smallball attack, now looks positively huge compared to some of these teams; their starting frontcourt goes 6’7″, 6’8″, 6’10.” A decade ago that would have been suicidal, but in today’s NBA teams can survive and even thrive with frontcourt players that size.

That takes us to the next trend: position creep. Two years ago if I mentioned that Richard Jefferson should play some power forward you’d have thought I was nuts. But in today’s game, why not? Play Jason Kidd and Marcus Williams in the backcourt, put Vince Carter at small forward, and play Jefferson at power forward. Sure, he’s only 6-foot-7, but chances are the guy he’s guarding is too. And if not, the rules allow Jefferson to blow by him on offense and have a zone to protect him on defense.

This is a very real factor in how the season will play out, because it means that teams that have been deliberately built to enjoy an excess of perimeter players are in much better shape than we suspected. The Nets could be one of the clubs to benefit. Their lack of frontcourt depth has been a constant topic of discussion, but if they can split the center spot between Krstic and Collins and play Jefferson and Nachbar as their power forwards on most nights, then the lack of frontcourt bodies isn’t nearly as big a problem.

On the other hand, depth in the backcourt becomes a much bigger issue. Thanks to the smallball revolution, the Marbury-Francis-Crawford alignment in New York seems much more plausible in this brave new world than it did a few years ago. (At least in terms of size, that is. It still has other issues, like that whole “sharing one basketball among three ball hogs” thing.)

Another commodity that becomes much more valuable is a guard who can rebound. With only one true frontcourt player on the court for much of the time, it’s incumbent upon the backcourt players to hit the glass. The Nets are in good shape here as well – Kidd and Carter were two of the top three guards in Rebound Rate last season – and Wednesday’s stats show just how big a deal the phenomenon might be this year.

Believe it or not, the top gatherer of defensive rebounds on Wednesday wasn’t Kevin Garnett or Dwight Howard or any of the other behemoths of the middle. It was Boston’s 6-foot-6-inch Paul Pierce, who snared 18 defensive caroms. Just a few spots down the list was Carter, who grabbed 11. Several other wings — Tayshaun Prince (9), Larry Hughes (9), Marcus Williams (8), and Mickael Pietrus (8) — were on the leaderboard , as well as recently converted wings like Tim Thomas and Lamar Odom.

The names on the offensive rebound leader list were just as unusual. Atlanta’s Josh Childress tied for top honors with eight, while Memphis point guard Kyle Lowry snagged five against the Knicks and Jason Kidd ripped four.

While the small guys run wild, “true” centers are slowly becoming extinct. Of the traditional centers, only four played more than 30 minutes in their team’s opener. One of them, the Knicks’ Eddy Curry, cleared the hurdle only because his team played three overtimes.

What we saw instead were converted power forwards (Emeka Okafor, Jermaine O’Neal, Murphy, Zach Randolph and Elton Brand) playing center, which makes sense since their old positions are now manned by all the converted small forwards.

All told, the big lesson from the first 48 hours of 2006–07 isn’t about one team or one player, but rather the league as a whole. Smallball is here to stay, and if anything the league is only getting smaller.

jhollinger@nysun.com