One theory about why Adrian Peterson decided to skip the Vikings' three-day minicamp last weekend and, instead, attend "Adrian Peterson Day" in Palestine, Texas, was related to the fact the running back might have looked at how Brett Favre was being treated and figured the same rules should apply to him.

Now another (potentially more expensive) theory has emerged. Mike Florio of the popular website Pro Football Talk has broached the subject that Peterson's absence might be contract related. First off, let's be very clear in saying we here at Access Vikings have no hard evidence that this is the case.

The Vikings don't comment on contracts or negotiations and Peterson's agent, Ben Dogra, has not returned numerous e-mails and phone messages seeking a comment. My former colleague, Kevin Seifert, who does an outstanding job on his NFC North blog for ESPN's website, took at look at Peterson's contract situation last month.

Seifert's point was that Tennessee running back Chris Johnson and Houston wide receiver Andre Johnson both weren't pleased with their contracts despite the fact the former has three years left on his deal and the latter is signed through the 2014 season.

"They have been among the NFL's most productive players in recent seasons and consider themselves due for a raise," Seifert wrote. "So why haven't we heard the same from the NFC North's top player?"

Is there a chance, however, we now know Peterson isn't happy? The seventh pick overall in the 2007 draft, Peterson received a six-year contract that would pay him a maximum of $40 million if he reached all of the incentives. There were $17 million in guarantees included. The reality is that the sixth year will void, so the contract really runs through the 2011 season.

Peterson's on-field success means he already has achieved many of the incentives contained in that rookie contract. Thus, he should make around $7 million in 2010 and will make at the very least a little more than $10 million in 2011. However, there is a possibility his 2011 salary could reach an eye-popping $13 million with escalators.

So why would Peterson want a new deal now? The simple explanation is because he's a running back and running backs don't have very long careers. Thus, Peterson and Dogra know it would be in their best interest to do an extension ASAP and include significant guaranteed money into the future. There is little doubt Peterson will want his next contract to make him the highest-paid position player in the league outside of quarterbacks. (The Rams' Stephen Jackson is currently the NFL's top-paid running back, having signed a $48.5 million, six-year deal in 2008 that included $21 million in guarantees.)

Peterson will be 27 years old in March 2012 and given how violent he plays there is no telling where the wear and tear on his body will be at that point. Peterson led the NFL in rushing in 2008 with 1,760 yards and in his first three seasons has run for 4,484 yards. His value almost certainly is not going to increase and in fact some could argue it already is set to decline.

Peterson averaged 5.6 yards as a rookie, 4.8 yards in 2008 and 4.4 yards last season. That final figure might have been partially the result of an offensive line that wasn't as sharp as the Vikings would have liked but it wouldn't be fair to put all the blame on the linemen. Other issues involving Peterson -- and ones the Vikings are sure to bring up at the negotiating table -- include his fumbling problems (20 in three regular seasons,13 lost) and the fact he has yet to prove he can consistently play on third down or in two-minute situations because of the pass protection skills required by a running back.

Peterson could go a long way toward answering those questions with a standout season in 2010. As far as if he was trying to send a message last weekend, keep in mind that Peterson showed up early in the week to do classroom work with position coach Eric Bieniemy before returning to Texas. Peterson had not been at any of the optional Organized Team Activities -- the minicamp was mandatory -- but he isn't the only player who elects to train on his own during OTAs.

But would Peterson have shown his face at all in Minnesota last week if this were an attempt to jump-start talks on a new contract?

Peterson and Dogra also have to realize that the Vikings, like many NFL teams, simply aren't doing extensions this offseason. The uncertainty surrounding the Collective Bargaining Agreement has left teams not knowing what the contract landscape will look like past 2010 and although there is no salary cap set for this coming season that doesn't mean there won't be one in 2011 and beyond. (Peterson's potential $13 million in earnings in 2011 could be an issue if there is a cap.)

What the Peterson camp could be pointing at, however, is the fact the 49ers gave star linebacker Patrick Willis an extension in May. Willis, the 11th pick overall in the 2007 draft, received a five-year, $50 million contract that includes $29 million in guarantees.

The Vikings have been extremely proactive since Zygi Wilf took over as owner in 2005 in doing extensions but that has not been the case this spring. Linebackers Chad Greenway and Ben Leber, wide receiver Sidney Rice and defensive end Ray Edwards all potentially could be unrestricted free agents after 2010 but there have been no known talks between those players and the team.

In a recent video posted on NFL.com, Bieniemy is shown working with Peterson in the classroom and talking about the patience the running back must show on the field. Peterson might not like it but if he wants a new contract odds are he's going to have exercise patience off the field, too.

A final thing: Some are going to point to the NFL's "30 percent rule" when it comes to Peterson's contract. That rule, which governs contracts that are entered into in a capped year and extend into the final year of the CBA, allows players to have future base salaries increased by only 30 percent when an extension is signed.

Peterson, for instance, had a 2009 base salary that was about $800,000. There are ways to try to get around the 30 percent rule -- although it's not cheap. The 49ers did it with Willis by giving him two signing bonuses (one in 2010 and one in 2011). None of that bonus money counts against the 30 percent rule.

The presence of this rule is another reason the Vikings probably want to wait before handing out any extensions.