In a city where neither local team has been three games over .500 all season, it may seem a tad presumptuous to wonder what’s wrong with a team playing .600 ball, but there’s something amiss in Cleveland.

The Cavaliers, 24–16 going into last night’s action, are on pace to match last season’s 50-victory total, and they currently have the best record in the East. But in a conference that’s substantially weaker than last season, that’s a big disappointment. Before the season started, this figured to be the first of several in which the Cavs reigned supreme in the Eastern Conference and possibly the moment for LeBron James and company to join the league’s elite.

Instead, the Cavs are playing middling ball. They returned to Cleveland last night after a West Coast road trip that included blowout losses to Denver, Phoenix, and Portland (Portland!). Although the Cavs’ winning percentage is a cool .600, their margin of victory according to the stat page at knickerblogger. net pegs them as a .556 team, which instead of a lofty 50 wins, puts them on pace for a pedestrian 45.

The obvious flaw is the offense. Last season, Cleveland finished ninth in Offensive Efficiency, but this year, they’ve dropped to 22nd. That drop-off has more than countered an improvement in their defense that has risen from 14th in Efficiency rating last season to fourth this season. Their offensive shortcomings were highlighted last month when they mustered only 63 points against Houston, and then two weeks later, they failed to break 75 in games against Orlando and Detroit.

Some of those low scores are owed to pace. After spending the first half of the season under coach Mike Brown, who is in his second campaign with the club, the Cavs resemble a unit directed by a protégé of Greg Popovich and Rick Carlisle. They’re a slow, defensefirst team. But without any offense, they’re going to be stuck in the middle of the pack.

Some of this season’s offensive decline can be laid at the sneakers of LeBron James. That guy from the funny Nike commercials has declined across the board. Most notably, his scoring is down four points a game from last season, and he’s getting to the line less. The drop-off is probably temporary and spurred by playing on the national team this season. Many pros struggle a bit after spending the summer in international competition. James’s Team USA teammate, Clipper forward Elton Brand, has suffered a similar downturn.

Decline or no, James is still averaging 27.1 points a game and shooting 47.7% from the floor. His teammates must shoulder more of the blame, and here’s where the bigger problems lie. Among the supporting cast, only Ziggy Ilgauskus, forward Drew Gooden, and guard Larry Hughes average more than eight points a game. Ilgauskus, a 31-year-old center, appears to be on a steady decline, though he’s still a productive player. Gooden, a 25-year-old power forward, has dropped a notch from his peak two seasons ago, but is young enough to turn things around. Hughes, who was signed two summers ago to be the solid no. 2 option for James, has either been injured or ineffective. He’s missed 11 games this season and is shooting 40% from the floor when in uniform.

After those three, the only useful players are backup pivotman Anderson Varejao and reserve forward Donyell Marshall. Most of the rest might as well be the Le-Brons of the Nike commercials. Two summers ago, general manger Danny Ferry sought to surround James with veteran role players, and some of the moves have not panned out — leaving the end of the roster full of guys well past their prime like David Wesley and Eric Snow, or specialists like Damon Jones.

In other words, with James, Gooden, Varejao, and a bunch of declining or declined vets, the Cavs may not get much better than they are now. They aren’t as good as Detroit and Chicago, but being a solid defensive team in the Eastern Conference should enable them to get a good playoff spot and a probable first-round exit.

Ferry will need to get busy this summer and rebuild the backcourt and bench before the Cavs fans can dream of the Finals coming to Quicken Loans Arena. The good news is that with James, Varajeo, and Gooden the frontcourt is more or less taken care of.

Because of the extension signed by James gives him an opt-out after the 2009 season, there’s a sense of urgency, but the Cleveland isn’t in a bad position. The Cavs are teetering around the luxury-tax threshold but Hughes has the only millstone deal, so there will be room to make changes. With their big men set, and a good coach in place, Ferry shouldn’t have much trouble rounding out the roster. But Cleveland’s slow start proves that they aren’t as far along as last season’s 50–32 record suggested.

mjohnson@nysun.com