The general discussion about the Cleveland Browns' defensive failures this season has revolved around one issue: Is the system so complex that it demands too much thought and not enough play?

Coach Mike Pettine and defensive coordinator Jim O'Neil have both said that the system is proven, and it's not too complex. One could make the case that during the first half in Kansas City it was too complex because the Browns gave up 17 points. But the same defense in the second half put up a shutout, so it couldn't have been too complicated during that part of the game.

Mike Pettine grew up in Rex Ryan's system, which ESPN analyst Bill Polian calls "exceedingly complex." AP Photo/Ron Schwane

In a recent story in the Buffalo News, ESPN analyst Bill Polian discussed the Rex Ryan defense, which is the system Pettine grew up in as an NFL coach and the system he runs in Cleveland.

To Polian, the system is far from simple. His comments related to the Bills' defensive struggles, and to complaints from several Bills players that the system was, indeed, too complex:

“You need veterans to make that defense work. First of all, the players thrived in another system [in 2014 under Jim Schwartz] – in a simple, straight forward, very easy to understand, very easy to communicate system where there was constant repetition of the same thing over and over again, taught in a very straight-forward way. And the techniques were geared toward what the players could do, what their skill sets were, and the plans were constructed around the players and what they could do. Rex’s defense is just the opposite. It is not straight forward. It’s exceedingly complex. There is no carry over learning from one week to the next. There’s exceedingly complex language. There are exceedingly complex checks that have to be made at the line of scrimmage. There is a guy designated to make those checks. It was ... Ray Lewis in Baltimore and it was ... Jimmy Leonhard with the Jets … I remember asking one of the Jets’ coaches during the offseason, ‘How in God’s name can you put Jimmy Leonhard on the field?’ He said, ‘No one else can translate the defense, no one else can get everybody lined up.’”

What's interesting is that Leonhard played such an important role for the Browns last season when he took over after Tashaun Gipson was sidelined with a knee injury.

The Browns touted him as a coach on the field. Evidently he was just that.

What's also interesting is that under Schwartz the Bills' defense ranked fourth in the league in points and yards allowed. Under Ryan, they have dropped to 16th in points and 20th in yards -- with largely the same group of players. The Browns under Pettine and O'Neil have ranked ninth and 29th in points, 23rd and 26th in yards.