Steelers Depth is a series aiming to dig into one hypothetical situation; every currently anticipated starter on the team is injured. Which positions could manage, which would struggle, where would the strength of the team be and where are its new weaknesses? No player is simply replaced. The face of the team automatically changes. This is a look into the quality of the back-up and based on their specific skills, the ability of that position to continue at the same level it was with the starter in place.
We've come to the bottom, where an injury to a starter is reason for great concern. It's a bad combination of an outstanding starter and a less-than-adequate back-up.
In the interest of full disclosure, with these two positions in particular, it's really more to do with the value of the starters than the back-ups, and in the salary cap era, teams don't have much ability to bolster their stars with great back-ups outside of the quarterback position.
Either way, it's fair to suggest the tight end position would lose a lot if starter Heath Miller went down. His absence would change much of the game plan, regardless of who's calling the plays.
In watching a replay of Super Bowl XLV recently aired on NFL Network, it's obvious Miller's value as a blocker isn't mentioned enough as a strength of him as a player, and to the Steelers offense. He flat-out owned OLB Clay Matthews on so many running plays, it was ridiculous. In fact, the critical moment of the game, a Rashard Mendenhall fumble to start the 4th quarter, can probably be attributed to the fact it was one of the few running plays called in which Miller was not on the play side. Back-up David Johnson and pulling center Doug Legursky missed blocks on DE Ryan Pickett and Matthews, who caused the fumble, flipping the game from the Steelers being down 21-17 with the ball on the Packers' 32-yard line, to Green Bay ball with a chance to ice the game.
The Packers scored a touchdown on that drive.
Miller is more than just an adequate receiver, but has been used mostly as an in-line blocker due to protection concerns along the offensive line the last three seasons. It's been said new offensive coordinator Todd Haley may look to get Miller the ball more down the field, and he proved his ability to get open in an outstanding Week 8 game against New England.
Miller going down, right now, would mean the insertion of either David Johnson or Leonard Pope into Miller's TE1 spot, and with all due respect to both players, neither are within the same realm as Miller is. The role of the tight end may be different between former offensive coordinator Bruce Arians' offense to Haley's, but Miller's value remains the same.
The logic is the same for strong safety. Troy Polamalu's impact on the game is so high, clearly, no back-up will ever be able to hold a candle to what he brings to the defense. The 2010 Defensive Player of the Year is never more than one step away from a game-breaking play, and, to put it mildly, it's unfair to ask back-up Ryan Mundy to come in and contribute in a similar fashion.
Mundy has proved himself to be a solid run supporter, but he lacks the dynamic playmaking ability Polamalu has. Very few in history can boast a similar ability. The face of the defense would categorically change without Polamalu on the field.