MINNEAPOLIS -- The Vikings retained another one of their free agents on Sunday, giving defensive lineman Everson Griffen a whopping $42.5 million over the next five years, including $20 million guaranteed, according to a league source.

Now what?

In the past five months, they have signed Brian Robison and Griffen to contract extensions, committing a combined $33.15 million in guaranteed money to the players. That would seemingly set their defensive end tandem up for the next few years, with Griffen replacing Jared Allen on the line. But wait, there's more!

Once the NFL's three-day negotiating window opened on Saturday, the Vikings made it one of their first priorities to express interest in former Cincinnati Bengals defensive end Michael Johnson, and put themselves in the middle of what will likely be a heated race for Johnson. The 27-year-old stood out at right end for new Vikings coach Mike Zimmer in Cincinnati, and the Vikings would have been working on Griffen's deal while calling about Johnson. But wait, there's more!

They also called about former Tennessee Titans cornerback Alterraun Verner, who played for new defensive backs coach Jerry Gray while he was the defensive coordinator in Tennessee and who has to be feeling emboldened today after news that Sam Shields signed a four-year, $39 million deal to stay with the Green Bay Packers. While the Vikings had more than $41 million in cap space last week, they have since signed Griffen and quarterback Matt Cassel, not to mention restricted free agent cornerback Marcus Sherels. They also reportedly brought back linebacker Jasper Brinkley for his second stint with the team, and according to a league source, they will host former Baltimore Ravens linebacker Jameel McClain for a visit on Monday.

While the pertinent question might be, "Who can the Vikings afford?" a better one might be, "On what does it make sense for them to spend their money?"

Without having seen the full breakdowns of the new deals yet, let's assume they account for about $16 million of cap space. That would still leave the Vikings with about $25 million of room for next season, with the cap likely to go up over the next few years. Paying both Johnson and Verner would be doable, but it could also chew up another $16-20 million in cap space for 2014, meaning the Vikings wouldn't have much leeway to sign tight end Kyle Rudolph to an extension, pursue other needs like a big-bodied nose tackle, or pay their draft picks. And in the case of Johnson, there is also the question of where the Vikings would use all their toys if they signed him.

Let's say Johnson came to Minnesota, filling the right end spot he played for Zimmer in Cincinnati. If Robison stayed at left end, the Vikings would be looking to move Griffen around again. He played 60.1 percent of their defensive snaps without starting a game last season, according to Pro Football Focus, but the Vikings aren't giving him $20 million guaranteed to use him in a part-time role. I think it's possible they could experiment with him at linebacker -- Zimmer likes his linemen to occupy blockers and allow his linebackers to run free, which isn't that different from a 3-4 scheme and could actually utilize Griffen's talents well -- but the previous regime tried a similar experiment, and the Vikings would have to see if Griffen could hold up in pass coverage. And with cornerback being a bigger need at this point, the Vikings might be better-served using their money to ensure they get an upgrade there.

It's also worth considering what Zimmer said last week, arguing for a reasoned approach to free agency while stating his preference for something with the dependability of a Ford F-150 over the flashiness of a Maserati. To this point, all the Vikings have done -- in fact, all they have been allowed to do by NFL rules -- is retain their in-house free agents. While they have expressed interest in two of the top defensive players on the market, that hasn't cost them anything yet. They could always clear more room by restructuring the contract of 31-year-old linebacker Chad Greenway, who is to make $8.7 million next season, and the Vikings still have enough room to do some contract gymnastics and sign a couple free agents while staying well under the cap, but for a team that has gone back to a draft-and-develop philosophy after years of shelling out for free agents, it might make sense not to get too carried away.

Could the Vikings still sign both Johnson and Verner? Yes. Would they have checked in with both of them so early, knowing Griffen's deal might get done, if they didn't have a scenario where they could land them? Probably not. But the size of Griffen's deal does mean the Vikings would have some pieces to fit in place if they were to get aggressive on the open market, particularly at defensive end.