Take one look at 1-for-13 shooting from the field, and it’s easy to write off O.J. Mayo’s showing against Chicago on Saturday as one of his bleakest of the season. But nobody in the Mavericks’ locker room saw it that way. Mayo clearly was bothered by the thick shoulder harness he wore to protect the sprained AC joint in his left shoulder that was revealed by his Friday MRI. He had trouble shooting the ball, going 0-for-6 in the first half. So at halftime, he ditched the brace and went with just a sleeve on his left arm. It didn’t help much. He still was awful shooting the ball. But he won the admiration of his coach and teammates by helping however he could in a must-win situation. “My shot’s a little broke right now,” he said. “But I didn’t want that to determine how I played. Sometimes the ball doesn’t fall, but there are other aspects of the game you can pick up in order to get the win.” Coach Rick Carlisle said he would use Mayo’s effort — playing through an injury that clearly wasn’t allowing him to use his left arm like he normally would — as Exhibit A for what the Mavericks need from everybody in the final nine games if the playoffs are going to be a reality. “Here’s a guy banged up, and I thought he was totally engaged in the game,” Carlisle said. “If we’re going to get where we want to get to, the example he set out there is really important — grit and guts, and being totally committed. I was proud of him. O.J.’s example is: ways to impact the game, even if you’re not shooting the ball well.”