So as the Patriots plan for life without Mankins -- with Kaczur sliding from right tackle to left guard, and Vollmer lining up at right tackle -- they'll first be turning to a pair of Gilbert-coached players.
They can only hope that Kaczur makes a similar impact as when Gilbert called on him in a pinch at Toledo.
Gilbert recalled the story Tuesday of how Toledo's starting left tackle in 2001 went down with an injury early in the preseason. When coaches gathered to discuss possible replacements, Gilbert spoke confidently that Kaczur -- a true freshman at the time who had enrolled in January after working two years of construction in Canada -- was the easy choice.
No matter that Toledo had not had a true freshman start on the offensive line since 1978, or that Kaczur had been limited in spring practices with a quad strain. Gilbert could already see that Kaczur was a "phenomenal practice player" who was also "very smart in terms of picking things up."
He was right in a big way.
Kaczur went on to start 51 games at Toledo, the coaching staff needing not worry about what had appeared to be a significant void at left tackle.
In New England, perhaps Kaczur will write a sequel to that Toledo tale, stepping in at left guard for the long term if Mankins has played his last game as a Patriot.
"He's big enough, he's physical enough and he's tough enough to move inside," said Gilbert, now coaching the offensive line at the University of Illinois. "Obviously, he's been in the offense long enough that he'd be fine assignment-wise. The change would be more technique -- footwork, with different pass sets. It's different inside than being out on the edge."
Kaczur's presence at left guard has been one of the more notable developments of this phase of the Patriots' offseason. The team has worked him at guard in the past, but that's solely been in practice to build more position flexibility throughout the roster. In games, all of Kaczur's action has come at tackle.
With Kaczur moving to guard, it's opened the right tackle spot for the powerful Vollmer, the 2009 second-round draft choice.
Should Mankins hold his hard contractual line, that's how the Patriots project to open training camp and, barring injury, the regular season.
The 6-foot-4, 315-pound Kaczur declined media interviews following Tuesday's practice, perhaps figuring he would be peppered about Mankins' situation and how it has appeared to contribute to his position switch. So, too, did veterans Matt Light (left tackle) and Dan Koppen (center).
Meanwhile, five-year veteran Dan Connolly, who emerged last season as a power fullback in addition to backup center/guard, said that any time he receives more repetitions it helps his development. So he's been a beneficiary of Mankins' absence in that regard.
Mankins' stand also puts a sharper focus on some of the team's younger interior linemen, such as 2009 fifth-round draft choice George Bussey, who spent his rookie season on injured reserve. Rich Ohrnberger, a 2009 fourth-round draft choice who is still not 100 percent physically from an undisclosed ailment, is also part of that group along with 2010 sixth-round draft choice Ted Larsen and second-year player Ryan Wendell.
But no one is affected more than Kaczur, and his college coach doesn't doubt that he's capable of filling the void.