More than one Big Ten coach has called Iowa's defense vanilla in the past decade.

It's not a dig at the Hawkeyes or at longtime defensive coordinator Norm Parker. Just the opposite, in fact.

Unlike some defenses, which have to mix up formations and plays until something clicks, Iowa gets by with a basic 4-3 scheme that relies on hard-and-fast rules, polished fundamentals and execution. And for the most part, the Hawkeyes have vanilla-d their way to success. The biggest key to the scheme is a line that can consistently generate pressure and reach the offensive backfield.

But Iowa now must replace three defensive linemen selected in April's NFL draft (Adrian Clayborn, Christian Ballard and Karl Klug). And at times last season, especially against spread offenses -- Arizona, Missouri, late in the Northwestern game -- Iowa's line didn't put enough pressure on the pocket, leaving some to wonder if a schematic shakeup was in order.

Could we see one this season?

I talked about this issue last week with Hawkeyes beat writer Marc Morehouse at the Big Ten spring meetings. Morehouse wrote in March about the possibility of Iowa using a 3-4 alignment more often this season. Although Iowa will remain a base 4-3, several factors suggest the defense will be more multiple.

From Morehouse's story:

Against the pass, expect Iowa to work in some 3-4 on passing downs, especially if that passer is (Blaine) Gabbert's caliber. Iowa will continue to rush four or more (but mostly four) probably 90 percent of the time, so we’re not talking wholesale philosophy change, just a tweak that would put more speed on the field.

It makes sense, especially against spread offenses that get the ball out quickly and require speedy defenders to make plays in space. Iowa struggled to generate consistent pressure against Gabbert in the Insight Bowl, forcing Parker to shake up the scheme quite a bit.

Without much proven depth on the line, Iowa might be well served by being more multiple this season. Although there are some question marks at linebacker, the group could be better and deeper if younger players like James Morris, Christian Kirksey, Anthony Hitchens and Dakota Getz continue to develop. Tyler Nielsen provides a veteran presence to build around, and Bruce Davis is back from a knee injury.

The biggest obstacle to a 3-4 is the lack of a mammoth defensive tackle. Iowa's tackles typically are a bit undersized, which has worked out well with players like Mitch King, Matt Kroul and Klug. Redshirt freshman Carl Davis, who checks in north of 300 pounds, is the only lineman who could fit the traditional 3-4 tackle mold.

Still, the depth issues up front combined with the potential at linebacker suggest we could see more flavors from a vanilla Hawkeyes defense this season.