SANTA CLARA — Both the 49ers and Cowboys’ first-team offenses played one drive in their preseason opener Thursday night. The Cowboys scored a touchdown on the opening drive of the game, while the 49ers yielded two first downs and no points. Jimmy Garoppolo and company watched the rest of the game from the sideline.

The Cowboys picked up two third-down completions to prolong their opening drive. On the first, a 3rd and 9, quarterback Dak Prescott bounced around the pocket and ran through a gaping hole up the middle for a 12-yard gain and a first down. The Cowboys later converted a 3rd and 1 with a two-yard run. The drive was capped with a 30-yard passing touchdown to wide receiver Michael Gallup up the sideline. Jimmie Ward ran alongside Gallup but halted his steps as he turned his head, leaving Gallup running free. He snagged the touchdown before 49ers free safety Adrian Colbert could help over the top.

The 49ers offense responded with a couple third-down conversions of their own. The drive opened with two Jerick McKinnon runs that yielded two combined yards. On 3rd and 8, Jimmy Garoppolo rolled to his right and found seventh-round pick Richie James for an eight-yard completion to move the chains. Three plays later, on 3rd and 10, Garoppolo stood in the pocket, withstood a hit, and delivered an 18-yard strike to Marquise Goodwin for a first down.

But McKinnon subsequently rushed for a six-yard loss. Garoppolo then overthrew tight end George Kittle on a post route, he crashed to the ground, and eventually left the game with a shoulder injury. On 3rd and 16, Garoppolo completed a pass to McKinnon for seven yards, and the 49ers were forced to punt.

That was all for both first-team offenses. Right guard Mike Person and right tackle Mike McGlinchey were the only offensive starters to remain in the game with the second team. Several starting defensive players played the second drive.

At the end of the first quarter, the Cowboys led the 49ers, 7-0.

The more important and developing story is that five 49ers players — Malcolm Smith, Kittle, Solomon Thomas, Matt Breida, and Garry Gilliam — all suffered injuries. Thomas lay on the ground for several minutes before he rose to his feet and sauntered to the locker room. All five players except Breida were escorted to the locker room.

The second preseason game is likely to see more action from the first-team sides.