The Rockets were trapped. The Memphis Grizzlies had put them in the grit and grinder they love so much. The Rockets were stuck in a half-court game, misfiring and getting whipped on the boards. But they had spent the past two weeks on an offensive roll. They were missing open shots Monday. They needed to move much more to get the overplaying Memphis defense from disrupting their offense. But if they could just rebound well enough to stay in the game, there was every chance their offense would kick in. They might not have seen it coming the way it did, with Dwight Howard and Jeremy Lin on the bench and James Harden out for a second consecutive game with a sore left foot. But once the Rockets found their shooting touch, they took off and rolled past the Grizzlies 93-86 in their first fourth-quarter comeback of the season. “We made a little statement offensively,” said forward Omri Casspi, who had 11 of his 16 points in the fourth quarter. “Coach (Kevin) McHale adjusted at halftime. We moved the ball better in the second half and made big plays. When we move the ball and share the ball together, it’s hard to stop.” McHale never did go back to Howard as Omer Asik held Zach Randolph to just two free throws. He did not call on Lin again until Francisco Garcia fouled out. But if the cast of characters was different — with the exception of Chandler Parsons, who made 8 of 9 shots for his game-high 17 points — the comeback was not unlike the Rockets’ season. They began shooting horribly, with the offense slow and stagnant. But once the ball and body movement picked up, they rolled. The Rockets had their worst shooting (16.7 percent) and lowest-scoring (12 points) quarter (second) of the season, falling behind by 12 heading into the second half. They went from that to hitting 70 percent of their shots, scoring 38 points in the fourth.