It only takes a few minutes of watching Pitt's defense practice to conclude that it is loaded with athletes who look to be interchangeable or, as some would say, "tweeners."

Pitt has several safeties who look big enough to be linebackers and run fast enough to cover receivers or running backs in passing situations and defensive ends who aren't that much bigger than the linebackers and run almost as fast.

Pitt defensive coordinator Phil Bennett calls them all "skill position players" and said the proliferation of the spread offense in college football forever has changed the way teams recruit.

And those "tweeners" -- like safety Elijah Fields, who is 6 feet 2, 225 pounds and runs the 40-yard dash in less than 4.5 seconds, or defensive end Jabaal Sheard, who is 6 feet 4, 250 pounds and runs the 40 in about 4.7 seconds, are the type of players every defensive coach covets.

"Offenses have gotten smart, and they are putting more skill-position players out there and making you cover them all," Bennett said. "It has completely changed the way we have to recruit.

"Now, we've got to find those what I call hybrid players to play linebacker -- kids who are smart and who are fast and maybe played other positions in high school."

Bennett said the spread offense is the "passing version of the wishbone" because the concepts are pretty much the same: The offense spreads the defense out and reacts to where the numbers favor the offense. If there are five defensive players in the box, the offense will likely run the ball. If the defense decides to put a sixth or seventh player into the box, the offense will react with a pass.

The concept of putting "hybrid" players on the defensive side of the ball is not new, especially not to Pitt coach Dave Wannstedt, who has been building defenses this way for nearly his entire career.

The difference is he started recruiting those kinds of players out of necessity because ,when he was an assistant coach at Oklahoma State, he wasn't able to recruit the big-time defensive linemen and linebackers like Big Eight powerhouses Nebraska and Oklahoma. So the staff compensated by recruiting players who may have been a half-step to slow to play their normal position and bulked them up a little and moved them forward -- from safety to linebacker or linebacker to defensive end.

Still, Wannstedt had been out of college football for 16 years when he was hired at Pitt after the 2004 season, and he wasn't that familiar with spread offenses. His ideas about building a defense, however, slowly but surely had become the norm.

Then he watched that 2005 team lose to several spread teams, culminating with a 45-13 loss to West Virginia. That's when he knew his top priority was to recruit more speed.

Wannstedt said that when the coaches go out to recruit defensive players, they have to do a lot more projecting of where recruits might play in college than they did in the past.

For instance, the two starting outside linebackers, Adam Gunn and Shane Murray, were quarterbacks/defensive backs in high school, and neither came into the program as linebackers. And defensive end Greg Romeus was a basketball star in high school, while defensive tackle Mick Williams was a fullback.

"When we go out and look at linebackers, unless it is an obvious linebacker, we're really looking for safeties who are a half-step slow to fill that position," Wannstedt said. "If you look at our defensive line and even most of our linebackers, I think Rashaad Duncan might be the only guy who actually played defensive line in high school or was recruited for that position, but the truth is there are very few teams who use a fullback any more, and you have to go get personnel to match up that way."