With the rush of free agency over (sort of), new rumors website (which as far as I can tell, is excellently run) NFLTradeRumors.Co reports via the NFLPA that the Vikings have $11,384,009 in cap space.

The NFLPA does have completely accurate information, but as NFLTradeRumors.Co indicates, it is not necessarily up-to-date. Others may have more up-to-date information but it isn’t necessarily accurate, as it usually relies on second-hand reports of contracts and structures. The NFLPA will also be off at times because of the post-season incentives charges to the cap.

As a result, there are different cap reports, from different groups.

My personal accounting for the cap leaves the Vikings with $11,684,900 of cap space before calculating the rookie contracts and $8,863,000 after including rookies. Despite the fact that the Vikings probably have around $6,578,416 devoted to rookies (in their “rookie pool”) that will be used for drafted and undrafted rookies coming in to camp, less than that will end up impacting the cap because only the “Top 51″ contracts are calculated into cap space.

Overthecap.com has a slightly different calculation, at $11,436,900 with a different Top 51, charging the Vikings with $121,348,617 (as opposed to my calculated charge $121,850,617). The reason I show more (marginal) space than the OTC calculation despite the fact that I had a larger cap charge is because OTC gives a different cap number than the league standard $133,535,517—they say the Vikings have $132,785,517.

The “standard” cap space applies to zero teams, and each team’s base cap number is adjusted from the “standard” because teams will still be charged for anything that they paid out that was not calculated in the calculation for the cap the year prior.

Calculated in the cost of any cap for a specific year are not just base pay and a signing bonus, but any incentives that are considered “likely to be earned”—LTBE incentives. Those can vary from player-to-player, and for the most part, those are determined by their performance in the previous year (rookie contracts deem all incentives as LTBE). All incentives that are in sole control of the player (workout bonuses, reporting bonuses, etc.) are LTBE. All other incentives are UTBE (“unlikely to be earned).

As you can imagine, not all players meet their LTBE incentives and many players meet UTBE incentives—Antoine Winfield, for example, was “set” to earn $3 million in 2012 based on his (injury-shortened) 2011 play. Winfield did have the ability to challenge the determination that reduced snaps would be the case in 2012 with an impartial arbiter, but didn’t—instead taking $3 million for taking nearly 90 percent of the snaps in 2012.

As happened with Winfield, and as happens with players on every team, there’s a difference between the LTBE and UTBE incentives actually earned. Two things happen in that circumstance: first, the team is charged their remaining cap space until they hit the cap limit for that year. Then, any remaining charge unaccounted for will deduct from the base cap for next year.

Second, the players UTBE incentives that were in fact earned become LTBE incentives if they’re still on contract for the next year (this second reason is why Winfield was released and perhaps related to why they didn’t attempt to renegotiate his contract—any playtime incentives would automatically be charged against the cap regardless of their actual intent to play him).

This system is why people were initially confused as to why the Washington Redskins didn’t “roll over” their unused cap from the previous year (you have to opt-in to roll cap space over). They didn’t have any to roll over, which the NFLPA report at the end of the season didn’t take into account.

In this case, the Vikings had a little less than $1 million in the difference between the actual LTBE incentives earned and the actual UTBE incentives earned. Things like playtime, performance bonuses (sacks, interceptions, etc.) and postseason honors (Pro Bowl, All-Pro) all play a role.

That explains why OTC is working off a different number, but we also have different total cap charges. This is because we have calculated the cap hit of a few players differently. They list the cap charge of Joe Berger as $635,000 and I have his charge listed as $985,000. It’s unusual, because they (and another site, Spotrac) give his base salary as $855,000 and his bonus as $65,000 but list his cap charge at $635,000.

The reason, I found out, is that players given veteran’s minimum will have a cap charge different from their salary. It’s part of the “veteran’s minimum salary benefit” negotiated by the NFLPA in order to make veterans easier for teams to sign. Functionally, that means there is a “cap discount” to sign a vet. So a cap hit for a player achieving the veteran minimum (with nine accrued seasons) is $570,000 even though the salary minimum is $855,000 in 2014. Add the signing bonus and his “true” cap hit is $635,000.

The same thing must have happened with Vladimir Ducasse, too. He is earning the veteran’s minimum for a player entering his fifth accrued year ($730,000) and I calculated his hit at $795,000 (another $65,000 signing bonus). OTC calculated his hit at $635,000 again. This softens my criticism of the Ducasse signing.

With those adjustments, OTC and my calculations agree.

After that, OTC and I disagree about the rookie charge. While we’re working from the same pool number ($6,578,416), we seem to disagree on the cap charge. Jason at OTC probably has figured out more about what constitutes a charge to the cap and what does not, but because the only rule I’m working from is the Top 51 rule, I calculated the cap charge of the rookies at $5,817,949 while OTC calculates it at $3,218,416.

There are some new rules this year regarding the freezing of the signing bonus for rookies that I didn’t calculate, but that should inflate, not deflate, the total hit. Regardless, my estimate puts the remaining Vikings cap at $5,626,951 and Jason’s likely more accurate estimate $8,218,484.

That’s a lot of space to roll over into an ever-increasing cap into 2015 (much of it likely be consumed by the 2013 rookies re-hitting their incentives, which were LTBE in 2013 but most of which are UTBE in 2014, so not therefore calculated this year) and a lot of wriggle room to work with as they hit the more “win-now” seasons of 2015 and 2016, where they can concentrate on high-impact free agent signings, as well as extend players like Kyle Rudolph, Cullen Loeffler and Jamarca Sanford.

At the very least, the Vikings are sitting pretty with how much money they have left to spend.