Was Clemson's pick legal? Pick plays are legal under certain circumstances

… Alabama defender initiated contact 

The play that Clemson used to win the national title has been described as a "pick play." Indeed, it was, but one problem exists.

At the collegiate and professional level, pick plays are legal as long as they are not considered to be pass interference or an attempt to pick a defender without running a pattern. At least that's the interpretation that I am seeing about this.

These plays are not new, but with new emphasis on the pass over the past two decades, the rules have been liberalized somewhat.

When I was coaching at the college or high school level in the 1970s and 1980s, we had players run crossing routes that were intended to clog lanes so that defenders could not follow the receiver.

Today, that is called a pick. Our plays were legal then as long as we did not screen the defender without running a route.

Humphrey made mistake

However, the pick play turned out to be legal for another reason. What happened on the final play was that Clemson receiver Artavis Scott ran into Alabama DB Marlon Humphrey, but the contact was welcomed, and perhaps initiated, by Humphrey. I watched the play numerous times today, and Humphrey grabbed Scott and threw him to the ground at his feet. That, of course, could have been called holding or pass interference, but it was not.

The defender who was supposed to be watching Clemson receiver Hunter Renfrow, who caught the winning TD pass, was Tony Brown. He had difficulty moving around Scott and Humphrey, but it was not because Scott had picked him. Instead, it was because Humphrey made no attempt to avoid the contact and was happy to take Scott out of the play.

This was not a pick. It was simply that Brown did not react quickly enough to the play. Case closed.

Even Alabama outside linebacker Tim Williams, who was arrested on a gun charge in Sept. but continued to play for the Tide, told Fox Sports' Bruce Feldman that a flag should not have been thrown on the play.

Reality
The truth is that with two seconds left, the Tide should have tackled or held every receiver on the play to allow the clock to run out. That would have been good coaching. The ball would have been moved to the one for the last untamed play, but Clemson would probably have kicked the field goal and forced OT.

Alabama had to stop that last play, but it did not, plain and simple. They knew that Clemson would run some kind of pick, and in this case, they did. But, it was not an illegal pick. 

Washington Post: "Yes, Clemson ran a 'pick play,' but it was completely legal:

https://www.washingtonpost.com/news/early-lead/wp/2017/01/10/yes-clemson-ran-a-pick-play-to-beat-alabama-but-it-was-a-legal-play/?utm_term=.ea598e02173c