The football equivalent would be the center, quarterback, middle linebacker and free safety.
Much as the catcher calls the pitches, the center makes the line calls. Like the pitcher, the quarterback does all of the precision throwing. Like the shortstop and second baseman, the middle linebacker operates in a high-traffic area. And, like the center fielder, the free safety has the most ground to cover. He often is referred to as "the center fielder of the defense."
Meyer won the 2006 national title with a defense spearheaded by Brandon Siler at middle linebacker and Reggie Nelson at free safety. With those two replaced by young players in '07, the defense slipped noticeably.
"You had Reggie Nelson and Brandon Siler, two of the greatest players in Florida history," Meyer noted at SEC Media Days earlier this year. "You replaced them with a true freshman and true sophomore that weren't ready for that, and our defense didn't play very well."
Meyer believes strength up the middle is just as vital on offense, noting: "The offensive line is five guys working together, and the apex is the center. The quarterback is managing the back six of the offense, so I'm a real strong proponent of that."
So, how does Tennessee stack up in terms of its strength up the middle?
Here's a quick look:
CENTER: With three-year starter Josh McNeil sidelined indefinitely, the Vol starter is 6-1, 260-pound former walk-on Cody Sullins. The fifth-year senior saw mop-up duty in five career games prior to starting Saturday vs. Western Kentucky.
QUARTERBACK: Jonathan Crompton is a fifth-year senior who struggled mightily in 2008, completing just 51.5 percent of his passes with more interceptions (5) than touchdowns (4). He opened 2009 in grand style, however, completing 21 of 28 passes for 233 yards and five TDs.
MIDDLE LINEBACKER: Like Sullins, starter Nick Reveiz is an undersized former walk-on. The 5-10, 220-pound junior had one career start on his resume prior to Saturday's 2009 opener vs. Western Kentucky.
FREE SAFETY: Dennis Rogan is a 5-10, 178-pound junior who had 12 career starts - 10 of those at cornerback - entering the 2009 season. He nearly lost the job to freshman Janzen Jackson in preseason camp.