We received a text message and a phone call late Saturday/early Sunday from a league source who shared with us a curious development regarding the Minnesota Vikings’ ongoing efforts to acquire Kansas City Chiefs defensive end Jared Allen.

Per the source, the Vikings are “likely” to sign Allen to an offer sheet after next weekend’s draft, if a “fair” trade can’t be worked out before then.

The move meshes with the idea that came us to like an acorn to a blind squirrel on Saturday.  With the Chiefs reportedly wanting a first-round pick and a second-round pick for Allen, why not simply nab Allen with a poison-pilled offer sheet and foist on the Chiefs the Vikings’ first-round picks in 2009 and 2010?

The fact that the Vikes apparently plan to pursue this tactic is a strong indication that Allen’s visit to the Twin Cities has resulted in an agreement between the player and the Purple regarding the money that will be paid to the NFL’s sack leader in 2008.

But there’s a wild card in this scenario.  The Tampa Bay Buccaneers are reportedly interested in Allen, and could be squeezed into besting the Vikings’ pre-draft trade offer if the Bucs know that Allen would otherwise be poised to sign a post-draft offer sheet in Minnesota.

Then again, if Allen has made up his mind that he wants to play in the land of 10,000 lakes (but hopefully not 0.10 percent BAC), the Bucs will be out of the picture, and the question will be whether the Vikings get him before the draft, or after it.

A couple of readers have asked us whether the Vikings could sign Allen to an offer sheet right now, since it’s less than seven days before the first day of the draft.  But even though a team with a franchise player has up to seven days to decide whether to match an offer sheet that he signs, the team can also decide before the seven days expire to not match it.  In this case, doing so would give the Chiefs the Vikings’ first-round picks in 2008 and 2009.

And since the Chiefs would surely prefer to get extra draft picks for Allen right now (especially since G.M. Carl Peterson might not be around to use picks in 2009 and/or 2010), it’ll be critical for the Vikings to dust off the poison pill, if they want to be sure to acquire Allen.  Otherwise, the Vikes will have merely negotiated on the Chiefs’ behalf Allen’s long-term contract to stay in Kansas City.