The Vikings came into existence as an NFL expansion team in 1961. They have been in the same grouping with the Green Bay Packers, the Chicago Bears and the Detroit Lions throughout that existence.

The Vikings, Packers, Bears and Lions have played two games apiece against one another in every season, other than in the strike year of 1982, when they played once because of the nine-game schedule.

Fifty-one seasons. That's long enough to refer to the Packers, the Bears and the Lions as the Vikings' ancient rivals, right?

The past two of those seasons have left the Vikings in previously unexplored territory. They take a 10-game losing streak vs. the NFC North into Sunday's finale against Chicago.

No matter the outcome, the Vikings will finish last in the division for a second consecutive year. This was accomplished by losing a tiebreaker to Detroit a year ago. This season's last-place finish has been much more decisive.

You can complain about those four losses in Super Bowls played in the '70s, and complain more bitterly about the fact the Vikings now have been absent from the big game for 35 seasons.

In truth, Vikings loyalists have had a pretty good ride. As evidence:

The Vikings went 3-11 and 2-11-1 in their first two seasons, 1961 and 1962. It took another 40 years for the Vikings to achieve double-digit losses in back-to-back seasons -- 5-11 in 2001 and 6-10 in 2002. Now, they have done it again, with 10 losses in 2010 and the 12 (or 13) this season.

As for those consecutive last-place finishes? The Vikings have never done that before.

But that reality is now here for the Vikings, last again, and you wonder if this might be the start of the first major downturn -- meaning, numerous seasons on the wrong side of .500 -- for the Purple Faithful to experience.

The Vikings haven't had three losing seasons in a row since their expansion infancy of 1961 through 1963. Certainly, the rivals have had more losing streaks to deal with:

The Packers had seven of eight losing seasons from 1973 through 1980, then five of six from 1986 through 1991. The Bears had losing seasons from 1969 through 1975, from 1996 through 2000 and again in this past decade -- 2002 through 2004.

The Lions' futility has been monumental, of course. They had streaks of losing seasons from 1976 through 1979, from 1984 through 1990 and from 2001 through 2010. The Lions were 39-121 over those 10 years -- 12 losses per season, as an average.

How bad can it get for the current Vikings?

First off, it's much more difficult for a team to put together a streak of futility in the salary-cap era. That makes Detroit's recent losing even more remarkable, and also reduces the odds that the Vikings will turn this into an unprecedented stretch of five, six losing seasons in a row.

And then you look at the enormous gaps in personnel, look at what coach Les Frazier and his staff produced in their first full season, look at the now uncertain future of superstar Adrian Peterson, and say:

"Large amounts of losing -- not Lions-like, but ongoing -- are possible, unless there's a decision-maker at Winter Park who can find a half-dozen defensive players, an offensive line and a receiving corps, and maybe a quarterback, and do it on the run over the next couple of years."

From here, the Purple futility of the past two seasons feels much different than at any time previously.

The Vikings were rebuilding after the combined 21 losses in 2001-02, but they had fewer gaping holes than this bunch. They didn't have entire position groups to fix: secondary, linebacker, receiver, offensive line.

Bud Grant had a mess to clean up on his one-season return in 1985, but CEO Mike Lynn helped mightily by bringing in Anthony Carter and Keith Millard from the USFL.

There's no USFL to draw on now. There's only the draft, and maybe a free agent or two that his previous team decides not to pay.

Gene Mauch, the old baseball manager, used to say that "snags" and "slumps" were very distinctive things for an athletic team. This feels like more than a two-year snag for the Vikings. This feels like a serious slump.

Patrick Reusse can be heard noon-4 weekdays and 10-noon Saturdays on 1500ESPN. • preusse@startribune.com