Safety Ryan Mundy will start on Sunday night against the Broncos for Ryan Clark, who is sidelined because the sickle cell trait he carries prevents him from playing in Denver's high altitude.
For Mundy, and safety Will Allen, the added responsibility doesn't change how they are preparing this week.
"It all starts with mental preparation, getting the game plan down, understanding what we are trying to accomplish in the game," said Mundy. "Also physically I still have my responsibilities on special teams so I have to make sure I am in shape."
It isn't the first time they have had to assume Clark's responsibilities when playing in Denver, and they are definitely up for the challenge.
"We have been here before," said Allen. "It's just a matter of preparing like I do every game. You never know what is going to happen, who is going to get hurt. Every week I prepare to play, to start, even if that is not the case. You never know what is going to happen. It's a big game and it's going to fun. Everyone is ready for it."
One of the main duties that will fall on their shoulders is communicating to the defense. Coach Mike Tomlin referred to Clark as "a great hub of communication for our defense," and it will be up to them to handle that.
"I have to communicate whatever we learn throughout the week in regards to formations, situations," said Mundy. "The safeties have to do that for the defense. I am just communicating what I see. The safety isn't the only position. Any tip anybody has they are communicating. We are always communicating. It doesn't always fall on a safety, but it is one of the major responsibilities of the safety."
And playing against Broncos quarterback Peyton Manning doesn't make it any easier. Manning doesn't like to show a defense much before the ball is snapped, so communication can be fast and furious.
"It's like a cat and mouse game," said Mundy. "We are waiting until the last second on the play clock to show what we are doing and he is waiting until the last second on the play clock to try to get a play called.
"It's going to come down to who executes the best. We can line up in every defense, but we still have to execute. That is what it is going to come down to."
It's going to be a good test for the defense as well, going against one of the top quarterbacks in the game right off the bat.
"It's a great opportunity, especially as a secondary," said Mundy. "You have to make sure you are ready. He has proven time and time again he can win games by himself. We have to make sure we are ready, focused and ready to execute.
"We are looking to pick up where we left off and that was the number one pass defense in the NFL. We are looking to build off of that and this is a great game to do it."
Running back Baron Batch (groin) and linebacker James Harrison (knee) did not practice on Thursday, after participating on a limited basis on Wednesday. Linebacker Larry Foote (ankle) did not practice on Wednesday back was back on the field Thursday.
