Perhaps pushing for purity in play is a premodern idea. Foreign soccer and the NBA see a fair share of flopping, and the NHL and NFL have more than one undetected cheap shot per season.

Fan purity is also declining, mainly because of fantasy sports. It’s impossible to watch an NFL game without somebody bringing up her or his fantasy team or asking to flip over to the fourth quarter of the Chief-Colt game to check on Pierre Garcon. It seems being a fan of a single team is over — unless that team is your team, named after a witty reference that will be outdated by season’s end.

I don’t play fantasy football anymore. It had nothing to do with incompetence or lack of interest. It really was a "moral" decision, because of the interference of "The Heifers" with the Vikings. But not everyone can resist the temptation of potential cash — especially in college — so here’s at least one opinion on guidelines to keeping separate your fantasies from reality.

Note: I’ll use the Jaguars as the hypothetical favorite team, because there aren’t actually Jaguar fans, so it really is hypothetical.

1. Don’t play anyone playing your favorite team:

This should be the golden rule, cardinal rule, or any other type of No. 1 rule. Even if it’s the playoffs in your fantasy football league, die-hard Jaguar fans should never be happy to see any success against their squad. If this seems totalitarian, the next rule could be the concession.

2. Draft no more than one player from your team’s biggest rival:

It’s tough to determine if the Jaguars have a rival, but let’s call it the Texans after the Gus Johnson classic from last season. Obviously, if Andre Johnson is available, then, yes, draft him. He’s a franchise player. But once you add Matt Schaub and kicker Neil Rackers, that’s not an exception. That’s espionage.

3. Have at least one player from your favorite team who’s not the star:

This is actually a positive to fantasy football, one of the few elements of the "sport" that’s mutually exclusive with real football. Drafting someone else besides Maurice Jones-Drew from the Jaguars accentuates a fan’s understanding of new players for a Jacksonville fan. Draft the third receiver on the Jags’ depth chart, Jarrett Dillard — yes, I had to look that up — and know who he is when other fans don’t.

4. If your team is in a close game in the fourth quarter, no fantasy-talk:

Like the girl at the party who endlessly talks about her boyfriend at another school in a group of single people, no one cares about your fantasy team during another tight game. Think of it in terms of relevance. The only two people that care about your relationship and your team as much as you are you and the other person involved — your boyfriend or opponent. And sometimes, they don’t even care. This shows a lack of loyalty to your NFL team because of a lack of focus on the here and now.

5. If your league’s prize is more than $100, then disregard these rules:

Eventually, I want to be part of the 1 percent and have protesters occupy my office’s street. Again as a college student, there’s a price for everything — even my NFL allegiance. So go ahead and do the research, but seriously, remember why you even watched the NFL in the first place.

I’ll bet it had nothing to do with a computer.