It appears the 49ers will be without two of their top cornerbacks Sunday when they play a quarterback with the last name of Manning.

The last time that happened, it didn’t turn out so well.

The 49ers aren’t expected to have the services of Tramaine Brock or first-round pick Jimmie Ward when they visit the Giants and Eli Manning on Sunday. Defensive coordinator Vic Fangio said Ward is likely out after he sustained an injury Sunday to his right foot, which had surgery on in March to repair a Jones fracture. Brock (hamstring) will also be sidelined, a source said Wednesday.

On Oct. 19, the 49ers were pounded 42-17 by the Broncos in a game in which Ward and cornerback Chris Culliver were sidelined and quarterback Peyton Manning threw for 318 yards and four touchdowns in three quarters.

On Sunday, the 49ers will face a less-imposing offense. The Giants (3-6) rank 18th in yards per game and 20th in points, but they aren’t without weapons. Manning has thrown 17 touchdowns, six interceptions and ranks 12th in passer rating (93.1).

Manning has benefited recently from the presence of wide receiver Odell Beckham Jr., New York’s first-round pick who missed the first four games with a hamstring injury. Beckham has 25 catches for 370 yards and three touchdowns in his first five NFL games.

Last week, he had seven catches for 108 yards in a 38-17 loss to Seattle, a performance that included a 44-yard reception that came after he beat All-Pro cornerback Richard Sherman on a double move. Sherman termed Beckham a “great player” after the game.

Today, the hard-to-impress Fangio termed him a “great receiver.” Beckham has 15 catches for 264 yards in his past two games and is the first Giants rookie receiver since 1983 to have back-to-back 100-yard performances.

“This guy’s the real deal,” Fangio said.

With Ward and Brock likely out, Perrish Cox will probably cover the slot in the nickel defense and rookie Dontae Johnson will assume Cox’s spot on the outside.

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Fangio said rookie outside linebacker Aaron Lynch will likely make his second career start with Dan Skuta still hobbled with an ankle injury.

Lynch and Ahmad Brooks will start outside with Aldon Smith possibly spelling both of them. Fangio said he didn’t know how much Smith would play in his return from a nine-game suspension.

“He’s rusty, but he’s a young good athlete who, I think, will get the rust off pretty quickly,” Fangio said. “Haven’t really decided how I’m going to play him on Sunday. I haven’t told the players yet because in my own mind I’m not sure yet how we’re going to use him and how much. So I’d like to see the next two days of practice first.”

Meanwhile, rookie inside linebacker Chris Borland (shoulder) shed the non-contact jersey he wore in practice Wednesday. Borland had three shoulder surgeries early in his college career – two on his left shoulder — but said his ailment isn’t connected to his past issues. He said he wore a con-contact jersey as a precaution.

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With nose tackle Ian Williams (fractured fibula) out indefinitely, Quinton Dial will likely assume his spot Sunday. It’s possible Glen Dorsey (biceps), who is on injured reserve with the designation to return, could be placed on the 53-man roster this week.

“I think Glenn’s close,” Fangio said. “I don’t know if he’s close enough yet. We’ll see how he does today and tomorrow. Hopefully he’ll have a little bit more freedom and feel confident with his arm and to be ale to go out and play.”

Twitter: @Eric_Branch