What is the secret to the Pittsburgh Steelers improved offensive line?

This week, Jeremy Fowler of ESPN broke down the Steelers hefty investment in their offensive line, reporting that 21-percent of the Steelers'  salary cap belongs to tackles, guards, and centers. Right guard David DeCastro and center Maurkice Pouncey are responsible for over $15 million of that sum.

Since the Steelers began to focus more on their line, quarterback Ben Roethlisberger has enjoyed better protection and running backs have benefited from more effective blocking. The investment in on-field personnel, however, only tells part of the story.

Pouncey was not even able to play in 2015, yet the offensive line still performed well enough to allow Roethlisberger to throw for just under 4,000 yards in the 12 games he started. In 2015 Roethlisberger was sacked only 20 times. In 2009, a year he started 15 games, Roethlisberger was sacked 50 times.

What else has made a difference for the Steelers? The addition of offensive line coach Mike Munchak to the coaching staff in 2014. Munchak is responsible for elevating the game of many key players on the line, and keeping Roethlisberger well-protected even in the absence of Kelvin Beachum and Maurkice Pouncey in 2015.

Munchak was inducted in to the Hall of Fame for his accomplishments as an offensive linemen during his time with the Houston Oilers. Though he was unsuccessful as a head coach for the Tennessee Titans, he has a long track record of excellence when it comes to the offensive line. This season, Beachum will not be with the Steelers, but Alejandro Villanueva has a season of on-field experience under his belt and Maurkice Pouncey will be healthy enough to play. With the addition of Ryan Harris, Munchak should have plenty of talent to work with.

The Steelers were smart to invest in key personnel, both on and off the field.