Looking for the next big short? Put the National Football League on the list, according to best-selling author Michael Lewis.

Lewis is the author of influential sports business books-turned-movies including “The Big Short,” “The Blind Side” and “Moneyball.” His latest book is “The Undoing Project.”

From Yahoo Finance. Story by Daniel Roberts, sports business writer at Yahoo Finance.

On our afternoon live show, The Final Round, we asked Lewis what part of the market might become the next “big short.”

He was hesitant to answer, saying, “You’re asking the wrong person … When people roll in with some big prediction and they actually seem really certain about it, be very suspicious of them.”

But after the live show, Lewis said: “The NFL has real business problems. The CTE issues… I’ll give you the next short: the NFL.”

Is the NFL next big short?

The league has weathered so many scandals and PR issues over the last few years, from head injuries to domestic violence cases to political protests. Might this season truly be the beginning of a decline for football? To put it in Wall Street terms: the NFL has enjoyed a long bull market, and bull markets eventually come to an end.

As of the halfway point of the current NFL season, TV ratings are down an average 5% compared to the same point last year, and nearly 20% from 2015. NFL sponsors are reportedly “nervous” amidst the ratings dip and the ongoing political controversy, and at least one, Papa John’s, has publicly said it will pull back on its NFL advertising.

Lewis, an influential thinker on sports leagues and their finances, may be on to something. On the other hand, he added that practically speaking, he’s not sure how a person would go about shorting the NFL just yet.

Read more at Yahoo Finance.