Lifted from a back-and-forth in the comments section of another article
We wrote a piece on Steelers wide receiver Markus Wheaton Friday, highlighting his career production - or the lack of it - at this point. To follow up on that a little bit, and to point out some other specifics that will be important as this season plays on, Wheaton is penciled in as the Steelers' "X" receiver right now.
What does that mean?
The X is the widest receiver - the split end. He's always on the line, which means he can always be jammed. You look for quickness to get off the line and straight line speed to get down the side line. They'll also probably face more man coverage, as most defenses will have the corner carry the split end up the sideline, but stay with their zone if the split end cuts inside.
The Steelers have an interesting past with their X receivers. Many have been highly talented and nearly all of them received more money to play somewhere else after not being retained by the Steelers. Two of them (Plaxico Burress and Antwaan Randle El) eventually came back to Pittsburgh. There are even whispers a third (Santonio Holmes) may be destined for a return.
Randle El took over for Plex in 2005, Cedrick Wilson took over for Randle El in 2006. Nate Washington worked in there for a bit until Holmes took over. Mike Wallace replaced Santonio with Emmanuel Sanders backing him up. Sanders got the job last year, and Wheaton is expected to start at the X this year. Rookie fourth round pick Martavis Bryant will likely eventually be the X, with Wheaton moving to the slot or the Z (flanker) in some fashion.
Brown is currently the Z receiver.
That's not all set in stone. They can move them around as they see fit, but the positions are all very different from each other.
The flanker is off the line, and goes in motion quite a bit. They are off the line because they're typically on the strong side (tight end side) of the formation, and going on the line means the tight end isn't an eligible receiver. You want great acceleration from those guys because they have to start a yard off the line, and because of that, they're not running deep routes. You want quickness and intelligence from those guys - they can turn and stop on a dime and recognize coverage. Often, they're the primary hot receiver on the quarterback's call.
The slot, or the Y, receiver, is typically lined up opposite the tight end but off the line of scrimmage.
(Editor's note: The Y receiver is often used to describe the tight end as well, something that was brought to my attention. The slot receiver can be called either just "slot" or "Y."
They are seam runners, and are often charged with finding holes in the middle seams of zone defenses. Often you'll see twins lined up on one side, and that's usually the X and the Y (outside-inside, on-and-off the line) with the TE and the Z on the other side. Teams are using slot cornerbacks (sometimes called the nickel corner, which is sort of misleading, considering teams like the Steelers have a starting CB like William Gay cover inside) to defend that position in 3WR sets. The Steelers will run a lot of "11 personnel" packages this year, which means there is 1 RB, 1 TE (hence "11") and 3 WRs. You'll see Wheaton as the X, Moore as the Y and Brown as the Z.
What's interesting here is how the team will utilize third round pick Dri Archer. It's simple to say he's a slot receiver, but to be honest, using him in motion is probably critical to Ben's presnap read, so I wouldn't be surprised if Archer works as a Z (look for PC's coming film breakdown piece going over the matter). That motion is important for the quarterback to be able to identify the defense he's seeing, and it's something Haley calls a lot of, so if Ben's at the line breaking down what the defense is doing to counter the fact Brown and Archer are on the field, he can logically deduce what their plan is for Brown based on how they react to Archer. That would mean Brown would have to play the X or the Y, which he certainly can do, but the Y is probably the most appropriate in an effort to maximize the team's speed.
Wheaton (4.4) Brown (4.4) and Archer (4.2) on the field at once with heavy, versatile mismatches like Bell and Miller creates a whole new world of dynamic playmaking ability. It's gonna be fun.