Will the St. Louis Blues regret trading Erik Johnson to Avalanche?

The St. Louis Blues and Colorado Avalanche pulled off the most shocking trade of the season at 1 a.m. on Saturday morning, meaning there's a good chance at least one member of each fan base returned from the bars, opened their computers, rubbed their eyes and assumed that Erik Johnson(notes) ending up in Denver was a whiskey haze hallucination.

Fact: Defenseman Erik Johnson, drafted first overall by the Blues in 2006 and a U.S. Olympian, is now a member of the Colorado Avalanche; and the Avalanche gave up some significant (and quite popular) assets to get him. From the Blues:

St. Louis Blues Executive Vice President and General Manager Doug Armstrong announced Saturday the club has acquired former first round draft choices Chris Stewart(notes) and Kevin Shattenkirk(notes) along with a conditional 2011 or 2012 second round draft choice from the Colorado Avalanche in exchange for Erik Johnson, Jay McClement(notes) and a conditional 2011 or 2012 first round draft choice.

"We're very excited to acquire a young emerging power forward in Chris Stewart and a top young NHL defenseman in Kevin Shattenkirk," said Armstrong. "These are two solid young players which will help us now and continue to grow and improve our team. I would like to thank Erik and Jay for their service to the St. Louis Blues and wish them nothing but the best of luck."

The deal was broken by Post-Dispatch writer Jeremy Rutherford. According to Bob McKenzie, the condition on the St. Louis 1st rounder is "it's top 10 protected. In other words, if St. Louis' 1st rounder is top 10 this year, Colorado gets 2012 pick instead."

Johnson signed a 2-year contract extension with the Blues last summer, and is a restricted free-agent after the 2011-12 season. Johnson wanted something long-term; the Blues wanted something short-term; and now, his term in St. Louis is over, the Blues having seen enough of him to leave him out of whatever it is they're building there.

Hopefully the golf carts are more well-behaved in Colorado.

A trade of this magnitude is about what you know, and what you don't know.

No one knows what Shattenkirk becomes after a promising rookie season. Stewart's an even wilder wild card: 6-2, around 230, a 23-year-old power forward who potted 28 goals last season and ruled the world in the first of this season ... until he broke his hand in a fight and scored twice since Jan. 14. Does he have upside, or has he reached a plateau as an NHL player?

Erik Johnson, you know. (Well, you also know what kind of defense you get from Jay McClement, and that he's inked through 2012, too.) Johnson plays 22:07 per game on average, on both the power play and shorthanded. He simply hasn't become the defenseman the Blues drafted him to be. GM Doug Armstrong dodged questions about trading Johnson left and right in this interview with the Blues website, but when asked about how tough it was to trade a former No. 1 pick, he said, "Not really."

As Jeff Gordon wrote last summer:

"He has the skill to become a 60-point scorer, but does he have the defensive instincts to become a Norris Trophy candidate some day?"

That's the hope for the Colorado Avalanche, who add a 22-year-old (23 in March) potential franchise defenseman to a team that (a) is absolutely loaded with young talent at forward and (b) has a few more young defenseman in the pipeline after Shattenkirk.

Two teams on the outside looking in at the playoffs just made a huge trade. One cut bait on a No. 1 draft pick. The other dealt two very promising players for a young defenseman who's already a solid pro and could be a spectacular one.

One is tempted to give the Avalanche the win here, but betting on Eric Johnson fulfilling his potential is what landed him in Denver in the first place, right?