If we can think of the nuggets of information linking Adrian Peterson to a possible trade with the Cowboys as a line of dominoes waiting only for a gentle push to really happen, then it's also instructive to consider this:

Some pretty interesting dominoes have been laid down lately, including word Thursday that the Eagles signed 2014 NFL rushing champ and now ex-Cowboys RB DeMarco Murray (thus opening a hole at running back that could be filled by you-know-who).

But a good number of the dominoes in the overall line — let's say at least 75 percent — were set down long before things turned ugly for Peterson in 2014 and even longer before any trust issues arose between Peterson and the Vikings.

In late August 2014, ESPN.com reported on a phone conversation Dallas owner Jerry Jones had in June with Peterson, during which an ESPN reporter who witnessed Jones' end said it "is obvious Peterson is telling Jones he wants to play for the Cowboys." Jones was quoted as saying, "I'd like that, too."

The conversation came months before Peterson was indicted by a grand jury on charges that he whipped his young son, and the publication came before it as well. After that report, Peterson issued a statement saying: "This was a casual conversation between NFL colleagues in which I never indicated I wanted to leave the Vikings. I have always said I understand the NFL is a business but that I would love to retire as a Viking."

It was a clear statement, but not a definitive statement. It left plenty to wonder if Peterson already thinking about what some NFL insiders were speculating about: that his salary and cap hit in 2015 could very well mean 2014 was going to be his last year in purple.

His affinity for Dallas is no secret. He said in a December 2013 Star Tribune interview, "I grew up a Cowboys fan and I'd always tell myself, 'I'm going to make it to the pros.' "

In January 2010, before the Vikings played Dallas in the playoffs, Peterson talked about meeting some of his Cowboys heroes for the first time: "I tried to keep my composure and stay calm. … I tried not to act too excited, but I was inside."

Dallas and Murray have been heading for a split for months. Peterson and the Vikings might have been heading for a split this offseason regardless of his off-field problems.

That doesn't mean a trade will happen. But those dominoes keep lining up, just as they have been for a long time.