On3's Andy Staples ranked the top 10 defensive coordinators in college football. The list, which was released on Thursday, said that Iowa Hawkeyes' Phil Parker is the No. 1.Here is what fans on social media thought about this list. Several believed that Michigan Wolverines' defensive coordinator Wink Martindale should be on the list."Wink not being on this list is a crime," a fan tweeted."Martindale is better than at least half of these people but whatever... On3 missing per usual," another fan commented."Wink Martindale held OSU and Bama to 23 combined points," one fan wrote.Others gave their opinions on Parker being No. 1 in the rankings."Hell yes! He has been one of the most consistent DCs for a decade. Year in and year out he has one of the top defenses. Should have won more awards," a fan commented."Phil Parker is terrible Iowa gets smoked by teams with a pulse," another fan said.Meanwhile, some fans also mentioned the lack of the Auburn Tigers' DJ Durkin in this list."DJ Durkin is missing off the list!!!" a fan wrote."This is just click bait. You have Bama's DC in the top 10 of all of College Football? While at the same top leaving out Durkin?!" another fan said.Why some may think Phil Parker is the best defensive coordinatorPhil Parker has been the defensive coordinator of the Iowa Hawkeyes since 2013. During that time, the Hawkeyes won three Big Ten west titles, giving them a spot in the conference championship game, where they were defeated every time.However, despite not being able to take the program to the upper echelons of college football, Parker has been able to turn Iowa into a defensive powerhouse. When facing programs of a similar calibre to them, the Hawkeyes are by far one of the best defenses in the country, rarely conceding many points.However, Iowa has been struggling to score points as well in recent years, as there have been numerous Iowa games that are low-scoring affairs.This strong defense, weak offense approach does not help them when having to face some of the Big Ten's major programs, where they tend to get easily beaten.