The trade for pass-rusher Jared Allen, whom it seems is already being groomed for the Minnesota Vikings’ Ring of Honor, has closed the biggest hole in an improving defense, leaving offensive needs to be addressed with the second-round pick in Saturday’s NFL Draft.

The case for an offensive lineman has been made here all week, but the team is set there, with five quality starters and capable backups Marcus Johnson, Artis Hicks and Chase Johnson. Only center Matt Birk, who has played 10 seasons, seems to be nearing the end of his career, although tackle Bryant McKinnie might bring about the end of his playing days with foolish, off-field behavior, so this unit should hold up a couple more seasons.

The key to this season, as it always seems to be, is the play of the quarterback. For the Vikings to become a playoff team and potentially challenge for the Super Bowl, Tarvaris Jackson needs to elevate his performance. If he plays well this season, the Vikings should be one of three or four teams with a shot to win the NFC.

Given that the team’s backups are Brooks Bollinger and Gus Frerotte, that’s a lot of pressure to put on Jackson, who missed time with leg injuries last season. If Jackson doesn’t show improvement, all the offseason moves — Allen, Bernard Berrian, Madieu Williams, etc. — will be for naught.

So it would be a prudent move to find another quarterback, and there should be a quality player available in Round 2. Boston College’s Matt Ryan is the only quarterback guaranteed to be chosen in the first round, leaving Louisville’s Brian Brohm, Michigan’s Chad Henne, Delaware’s Joe Flacco and USC’s John David Booty as players who could be selected when the Vikings make their first choice of the day at No. 47.

If Jackson fails this season, none of these guys would likely be ready, though Brohm might be the most pro-ready after directing the wide-open Louisville offense. However, if Jackson doesn’t cut it, and the Vikings wait until next year to draft a quarterback, several of the team’s stars — Birk, Pat Williams, Darren Sharper, Antoine Winfield — will be a year older with skills that begin to diminish.

Jackson remains too much of a gamble, and extending that risk for another year makes no sense. If Jackson becomes a competent starting quarterback, the worst thing that happens is Bollinger files for unemployment compensation. Despite former coach Denny Green’s assertion that he once coached a team without a weakness, this is a rare time in the team’s history where the are no obvious needs for the upcoming season, making this an ideal situation to bolster the quarterback position.

Barring a trade, the Vikings are unlikely to own a draft choice high enough to select a “franchise” quarterback in the near future, so adding one in the second round gives the organization some margin for error.

Chad Courrier is a Free Press staff writer. To contact him, call 507-344-6353 or e-mail at ccourrier@mankatofreepress.com.