Dick LeBeau understands the gravity of the challenge the Steelers will be facing in trying to replace three injured defensive starters on Sunday afternoon against Tampa.

The Steelers' defensive coordinator has done the math.

"It's basically one-fourth of your starting lineup," LeBeau said of losing inside linebacker Ryan Shazier (knee), outside linebacker Jarvis Jones (wrist) and cornerback Ike Taylor (forearm) in last Sunday's 37-19 win at Carolina.

Cornerback William Gay is, in effect, a fourth deletion from what would be considered a 12-man starting lineup since Gay will replace Taylor and someone will in turn have to replace Gay as the nickel back in sub-package situations.

"We're fortunate that we have some good people behind them," LeBeau said. "We'll have to adjust. It won't be the only game during the season that this situation will arise, I'm sure of that.

"We try to prepare for this starting in coaching sessions (OTAs) and up into training camp, try to practice for Plan B and Plan C. Many a game I've been in you had to go to Plan D and Plan E. At least we've been through the scenario.

"I thought our guys did a good job of staying focused (in Carolina). We gave up some plays later in the game but we were able to get off the field and keep the score relatively low."

Veteran Arthur Moats replaced Jones and third-year pro Sean Spence took over for Shazier in the Carolina game and are in line to do so again. Moats and Spence played defensive snaps at those positions this season prior to entering as injury replacements against the Panthers.

Third-year pro Antwon Blake was the third cornerback deployed after Taylor went down in Carolina. Blake, second-year player B.W. Webb and sixth-year pro Brice McCain are competing for sub-package duty this week in practice.

Veteran James Harrison, re-signed this week, likely will figure into the picture at outside linebacker as well.

"I don't think (head coach) Mike (Tomlin) brought him back to not dress him," LeBeau said.

However the personnel adjustments shake out, LeBeau is confident the work-in-progress defense will continue doing what's necessary to keep making progress.

"We haven't proven one thing one way or the other yet," LeBeau said. "Everybody in the whole league is kind of in the same boat right now. We certainly didn't get off the way that I wanted us to, and these are important games for us here coming up. I don't have any doubt about the work ethic and the commitment of these guys. It's how we can play together and how productive we can be, and that remains to be seen.

"I have confidence that they will work until they get to where we need to be."