HOUSTON - The Houston Rockets will have to depend on their defense until Tracy McGrady gets healthy because they sure can’t rely on their offense.

With their star out for three weeks with a back injury, the Rockets (1-2) open a five-game road trip Thursday in Miami. It looks like a tough stretch for a team that has averaged 36 percent shooting and blown fourth-quarter leads in consecutive home losses to New Orleans and Orlando.

“We’re just not very good right now,” guard Jon Barry said. “It’s disappointing because the easy thing to say is that Tracy’s not here. But we’re good enough. There’s no excuse.”

McGrady strained his back doing a reverse layup in practice Friday. Without him, Houston coach Jeff Van Gundy has mixed up lineups, looking for the right combination to generate points.

So far, he hasn’t had much luck.

Yao Ming scored 17 points in Tuesday’s 76-74 loss to Orlando, but went 6-of-15 from the field and missed a short hook shot in the final minute. Since McGrady got hurt, David Wesley is 1-for-11 from the field, Derek Anderson is 6-of-21 and Stromile Swift is 5-of-17.

“We’re just struggling,” Van Gundy said. “Yao’s historically been a very high percentage shooter, Stromile’s not making and no one on the perimeter is making. That basically covers it. We’re struggling to make shots.”

Houston still should’ve won both games, thanks to a defense that’s holding opponents below 40 percent shooting. The Hornets and Magic went a combined 60-for-155 from the field (38.7 percent).

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But the defense has failed as badly as the offense has in the final minutes of both losses.

The Hornets finished their 91-84 victory on Saturday with a 17-2 run, hitting their final six shots. The Magic trailed 71-67 on Tuesday night before Jameer Nelson sank consecutive wide-open 3-pointers and a layup in the last two minutes.

“We should be 3-0, there are no ifs, ands or buts about it,” guard Rafer Alston said.

The rugged road trip includes visits to New Jersey, Boston, Minnesota and San Antonio. All but Minnesota made the playoffs last season, and the Timberwolves just missed, finishing 44-38.