The 49ers’ first play of the game went to rookie wide receiver Brandon Aiyuk, which was a hint of things to come Sunday.
Aiyuk, for whom the 49ers traded up six spots to take in last spring’s NFL draft, had something of a coming-out party in the 49ers’ 36-9 win over the Giants at MetLife Stadium.
After being out with a hamstring injury in Week 1 and seeing limited action in Week 2, Aiyuk was a major part of the 49ers’ game plan in Week 3.
“It was fun to get out there and get my feet wet,” Aiyuk said. “Last week I got the feeling out of the way to know what it would be like. So, I was excited to get to work this week, and I knew I would be more of an option.”
The 49ers have no time for rookie growing pains right now. Not with so many of their players out injured. It’s next man up, even if you only have two seasons at Sierra College and two seasons at Arizona State under your belt.
With Deebo Samuel out with an injury, 2019 starter Emmanuel Sanders in New Orleans and Dante Pettis still not an effective option, Aiyuk got the start, along with Kendrick Bourne. And with primary receiving target George Kittle still sidelined by a knee injury, Aiyuk saw plenty of action.
“I was happy with Aiyuk,” coach Kyle Shanahan said. “He struggled a little in the first half, but then got going in the opening drive of the third quarter.”
What exactly were his struggles, Shanahan was asked.
“I shouldn’t have said that,” the 49ers coach said. “The struggles are to my own standard. He was by no means bad. … I thought he was a lot more aggressive in the second half with his routes.”
That’s some insight into the demands Shanahan puts on his players. Next man up, next number called, and you’re expected to perform.
“The more guys you have that can run the ball and catch the ball, it gives you a lot of options,” Shanahan said. “It helps you with injuries, too.”
Aiyuk did both. He ended up being targeted eight times and had five catches for 70 yards. He also rushed three times for 31 yards, 19 of which came on a third-quarter carry, with three blockers ahead of him opening up a massive hole to the end zone.
Aiyuk also had the support of his young backup quarterback. He said Nick Mullens, starting for the injured Jimmy Garoppolo, was calm in the huddle and on point.
“Especially talking to me with some of those early mistakes,” Aiyuk said. “He kept me involved, kept my head right.”
Now that Aiyuk has gotten his feet wet, expect to see more of the rookie from Reno.
“You take every single week as if you’re the focal point of the offense,” he said. “That’s how you get better.”
Ann Killion is a San Francisco Chronicle columnist. Email: @annkillion