Miami made a few assistant coaching changes this offseason. So who is in the spotlight headed into 2015?

Assistant: Randy Melvin

Title: Defensive line coach

Since Al Golden arrived at Miami in 2011, no defensive lineman has gotten more than five sacks in a season. AP Photo/Rogelio V. Solis

Why he's in the spotlight: Pretty simple. The Miami defensive line has not come close to resembling the groups of the Hurricanes' heyday for years now. Nobody is winning the line of scrimmage. Nobody is busting gaps and taking down running backs in the backfield play after play. Nobody is a menace to quarterbacks. The numbers are disconcerting for anybody who remembers just how much damage the trademark Canes teams did up front. Last season, defensive linemen combined for seven of the team's 27 total sacks. Linebacker Thurston Armbrister led the team with five sacks. Since Al Golden arrived at Miami in 2011, no defensive lineman -- or anybody on the team for that matter -- has gotten more than five sacks in a season.

This helps explain why the Miami defense hasn't gained much traction over the last several years. To partly explain why, those who follow Miami closely will tell you defensive line has been hit hardest by scholarship reductions from the Nevin Shapiro scandal. Depth has been nonexistent, and Miami has often had to go the junior college route to plug holes. Still, the Canes signed nine four-star defensive linemen between 2011-14, and none have truly reached their potential.

At least not yet. The hope is that Melvin will be able to develop the talent remaining on the line from those classes and turn them into a dominant, physical line.

Miami must get production out of Jelani Hamilton, Al-Quadin Muhammad, Chad Thomas, Trent Harris, Anthony Moten and Calvin Heurtelou -- all players rated four-star recruits or higher. Not to mention Earl Moore, Mike Wyche, Courtel Jenkins and Corey King -- players the coaching staff believes are ready to take the next step.

Melvin has spent more than 30 years coaching defensive linemen. In 2009, he was on Golden's staff at Temple, where he helped develop future first-round pick Muhammad Wilkerson. He's tutored many other good defensive linemen in his past. But none of that will matter if he can't make this group any better in 2015. For Miami to show improvement, its defensive line must show improvement.