After a disappointing loss in Cleveland last week, Eric Mangini will look to get his San Francisco 49ers defense back on track at home, where the unit has been among the NFL's best.

The 49ers defense has allowed a league-low 15.8 points per game this year at Levi's® Stadium.

This week, San Francisco welcomes the first-place Cincinnati Bengals to town. The AFC North leaders will be without starting quarterback Andy Dalton, who will miss the game with a thumb injury.

In his Thursday press conference, Mangini spoke about Arik Armstead, Gerald Hodges and Ian Williams as well as Bengals backup signal-caller A.J. McCarron.

How has Armstead played against the run?

"I think Arik's done some really good things against the run. I think the thing with Arik and Eli (Harold) and (Jaquiski Tartt), all those young guys that are playing in the box, is some runs they've seen a lot, some runs they've only experienced a few times.

And the speed with which those runs hit, the fits, the feel, you can coach it, you can practice it, but you just don't get it at that same level. You've got to experience it and some of this is growing through that."

What have you been seeing from Hodges?

"I think what Gerald and I have talked about is sometimes you can hurry but you don't rush. He's very quick to see things and very quick to react, but you can be too quick, you can be too fast. There's a patience that has to come with those run fits, because even though you're working to the front side A-gap, you have the backside A-gap and so until that running back commits front side and there's no chance of cut back, you can't either.

You've got to be at that same depth so that you can react when he reacts. I like Gerald's aggressiveness. I like all those elements to it. But it's just sometimes you've got to slow it down a little bit and counter your tendency to get there too quickly."

How valuable is Williams to your defensive scheme?

"Ian is outstanding. ... I've always admired how he worked. And that's something that regardless of where you are on the field, you can always appreciate work ethic and that to me is one of his greatest characteristics, greatest assets.

Plus, he's also very steady, very consistent, very coachable. He's a really good role model for the young defensive linemen and he's a great story, a guy that has worked his way up and become a really good player."

What are the challenges of facing a backup QB like A.J. McCarron?

"Whenever you're dealing with a backup quarterback, especially in his first start where he's got the full week of preparation, is you don't have a ton of game film, that's one component of it. The second thing is you don't know what their feeling is on what he can and can't do well versus what the starter can and can't do well.

But they obviously have very strong feelings on it. So you're preparing for the system. You're preparing for things that he does and strengths that he has, but maybe there's plays that he really likes that you're going to get more of."