Building rivalries isn't always easy.

The Sun Belt Conference believes rivalries are geographic in nature.  And, to some extent, they are.

Louisiana and ULM traditionally play the final week of the regular season (although last year it was the first conference game for the Cajuns.)  And, sometimes there's something on the line.

But in football, ULM is not the Cajuns' biggest rivalry.

Georgia State and Georgia Southern are relatively new when it comes to playing each other.  Georgia State's program hasn't been around that long, while Georgia Southern is steeped in tradition and history in the game of football.

In football, Georgia State is not Georgia Southern's rival.

And, although Troy and South Alabama haven't played that much, since the Jaguars' program isn't very old, this one actually is a rivalry.

When you look at three of the games scheduled this week in the league, it's fair to say THIS is rivalry week.

TROY AT SOUTH ALABAMA (TONIGHT on ESPN2 at 7:00)--Anyone who didn't think it was a rivalry before doesn't say so now.  Not after last year, when the Trojans were flying high after a win over LSU, while South Alabama was getting ready to fire its coach.  South Alabama promptly brought the Trojans back down to earth with an upset win at Troy.  The Trojans didn't like it much.  And, really didn't like some of the smack talk after it was over.  Troy has lost its quarterback.  South Alabama is struggling at 2-5.  Doesn't matter.  They'll get it on tonight.

APPALACHIAN STATE AT GEORGIA SOUTHERN (THURSDAY on ESPNU)--Fans who don't follow FCS football that much won't understand, but this is the most bitter rivalry in the league.  It goes back to the days of the Southern Conference when these two programs were about as good as it got...not in the league...but in the country.  It's simply called "Hate Week."  And this year, there's plenty to play for.  Georgia Southern is 6-1 and App State is 5-1.  The Mountaineers have just moved into the AP Top 25 for the first time in school history.  Georgia Southern has the best home winning percentage..  Something has to give.  Oh, and the winner gets an upper hand on the possibility of hosting the Sun Belt Championship game.  You think this one isn't heated?  On the Sun Belt Message Board (csnbbs.com), the thread between the two schools is nineteen pages long as of noon Tuesday.  We're still more than 48 hours away from kickoff.

ARKANSAS STATE AT LOUISIANA--If there's one football rivalry that the Sun Belt can hang its hat on, it's this one.  The schools have been playing for a long time.  And, it seems when one has been good, so has the other...and vice versa.  In 1997 and 1998, the Cajuns combined for three wins.  Two of them were against Arkansas State.  Except for the 2000 season, these teams have been meeting annually.  Arkansas State's win in 2005 kept the Cajuns out of the New Orleans Bowl.  In 2014, players were ejected and reprimands given.  In 2016 the Cajuns won on a replay review and were quick to let Arkansas State know about it.  The Red Wolves gave the Cajuns a medicine game as a reminder last year.  These teams do not like one another.  It will be Billy Napier's first taste of the rivalry.  Oh, and the home team almost always wins.  The Red Wolves have won at Cajun Field once since 1992.  The Cajuns have won twice in Jonesboro in the same time frame.

Yep, with all due respects to in-state foes and the Sun Belt, history is what makes rivalries what they are.

Welcome to Rivalry Week in the Sun Belt.