Trading captain Eric Brewer was the tip of the iceberg for the St. Louis Blues. GM Doug Armstrong early Saturday delivered another deal -- a blockbuster -- by sending former first overall pick Erik Johnson and his top defensive center Jay McClement to the Colorado Avalanche.

In exchange, the Avalanche sent forward Chris Stewart and defenseman Kevin Shattenkirk to the Blues. A swap of picks in the next two drafts completed the deal.

The St. Louis Post-Dispatch, Denver Post and NHL.com confirmed the trade, which took place after the Blues' 3-0 victory over the Buffalo Sabres. The Blues play Saturday at home against the Anaheim Ducks. The Avalanche play Saturday night on the road against the San Jose Sharks.

The Denver Post described the deal as shocking and says the Avalanche have "decided to enter a new phase of rebuilding what was considered a young, up-and-coming team just a few months ago."

Both teams are struggling to get into Western Conference playoffs, trailing a cluster of teams. The Blues are 13th in the West, seven points out of a playoff berth. The Avalanche are 14th, 11 back. The Avs fell out of playoff position after nine consecutive defeats.

It was the second deal in less than 24 hours for both teams. The Blues sent Brewer, their captain for the past three seasons, to the Tampa Bay Lightning for a pick and a prospect on Friday. The Avalanche swapped No. 1 goalies with the Ottawa Senators, getting Brian Elliott in exchange for Craig Anderson.

In addition to the four NHL players involved in the trade, the teams exchanged picks in the next two drafts. The Blues receive a conditional second-round pick in 2011 or '12 and the Avs will get a conditional first-round pick in '11 or '12.

"We're very excited to acquire a young emerging power forward in Chris Stewart and a top young NHL defenseman in Kevin Shattenkirk," Armstrong said in a statement.

Avalanche GM Greg Sherman echoed Armstrong's enthusiasm at the deal.

"We are excited to be adding a top young defenseman in this league, a player who will have an impact on our blue line for several years to come," Sherman said in a statement. "In addition, Jay McClement brings six years of NHL experience and will compliment our young hockey club. He will also have an important role on our penalty killing unit."

"Moreover, the acquisition of an additional first-round draft pick represents a valuable asset and is a key component of this overall package."

The move is stunning for the Blues. Johnson the first overall pick in 2006, was considered the centerpiece of the Blues' rebuilding efforts. Viewed as a budding No. 1 defenseman, Johnson has five goals and 14 assists in 55 games. He is 6-4, 220 pounds and turns 24 in March. He is a coveted righthanded shot and was recently playing alongside another elite prospect, Alex Pietrangelo, especially as power-play points.

It might be Pietrangelo's emergence that led the Blues to see Johnson as expendable. And although believed primed to become the Blues' best defenseman, Johnson struggled this season despite extensive playing time -- most of which came when more veteran defensemen were out of action with injuries. Johnson was a member of the United States Olympic team that took silver in Vancouver last winter.

McClement, a six-year veteran, has six goals and 10 assists. He is a top-notch defensive center, long the team's primary matchup for opponents' best player.

According to the Post, McClement is viewed as a plugger with limited foot speed and offensive skill.

Stewart's season was derailed when on Nov. 27 he broke his left hand in a fight. He struggled when he returned. The Denver Post said the team had concerns about his defensive play, but added: "It clearly is a risky endeavor for the Avs to give up on a player considered by many to be one of the better young big forwards in the league."

The Post also said Shattenkirk's play had slipped after a strong start and that he, too, was seen has being a concern in defensive play. However, he is a viewed as a promising offensive player, and the Blues have dependable defensive defenseman to support him.

Stewart, 23, is 6-2, 228 pounds and will be a plus for a Blues forward group which lacks size among its top skilled players. He will join David Backes as a top-six power forward. And he has a history of scoring, with 52 goals and 61 assists in 166 games. He had 28 goals last season.

Stewart was the 18th overall pick in 2006, the draft that saw Johnson go No. 1 overall.

Shattenkirk, 22, is a rookie, second among first-year defensemen with 26 points in 46 games. He was the 14th overall pick in 2007. He took part in the recent NHL All-Star Game as a rookie representative.

Here's how the Post describes the decision on the picks the teams swapped. "If the Blues finish among the 10 worst teams by the end of the season, they have the option of giving their first-round pick to Colorado in 2012 instead of this year. If that option is exercised, Colorado would give up its second round pick in 2012 as well.

"If the Avs do wind up with St. Louis' first-round pick this year, they will have two in the first round overall."