Malcolm Subban was expected to make his NHL debut the past Wednesday night in Edmonton.

Bruins coach Claude Julien, however, put the last-minute kybosh on that decision, opting to go with Tuukka Rask in what turned out to be a 4-3 shootout loss to the hapless Oilers.

Two days later, the Bruins rolled into St. Louis on the fourth leg of a five-game road trip — without a win in the first three against the lower tier of the Western Conference.

Last night, the opposite against the upper echelon of the West in St. Louis; tomorrow the sad saga ends in Chicago against the highly touted Blackhawks.

After going 9-1-4 in their previous 14 games, the Bruins are now 1-6-1 in their last eight.

“He’s our goaltender tonight,” Julien said about starting Subban against the Blues to jumpstart his charges. “He’s a good goaltender and I expect our team to play well in front of him.”

Subban was 10-10-3 in his 23 starts in Providence.

Brian Ferlin also made his first NHL appearance on the fourth line with Daniel Paille and Gregory Campbell.

NESN analyst Gord Kluzak said before the first faceoff: “The Blues have so much depth, you can’t decide who to focus on for coverage. St. Louis is a tough test [for Subban]”

“You’re going to need your “A” game,” NESN’s Andy Brickley emphasized.

So, how did round 4 of the western swing go for the Black and Gold that entered the game without a win in its last five games and but one in February, while clinging to a scant one point advantage over Florida for the last playoff spot? The Panthers put on a resiliency show Thursday night in Montreal, spotting the Habs a two-goal lead before clawing their way to OT and a 3-2 shootout win.

The steely Blues were 7-3-0 in their last 10 games and a sparkling 21-6-2 at home in the Scottrade Center. All good for a playoff lock behind Nashville with the best point total in the NHL at 84.

It looked good for Subban and the Bruins.

For one period.

The first 20 minutes were one of the best for Boston this season, holding the Blues to three (weak) shots on Subban – none in the first 12 minutes, while Brad Marchand handcuffed Blues’ backup Jake Allen at 10:42 with a 20-foot wrist shot for his 17^th – Patrice Bergeron and Reilly Smith assisting.

“Outstanding first period,” Brickley summed about the 1-0 lead.

The second frame? A polar opposite.

Among the NHL’s best in second-period production, the Blues put on a clinic to dismiss any Boston momentum with four goals in less time than it takes to fill a food order during intermission.

Forty-eight seconds in on a 4-on-4, Blues defenseman Peterri Lindbolm blasted a 50-footer past Subban from the point for his first goal of the season.

Three and a half minutes later at 4:06, defenseman Alex Pietrangelo put the Blues up for good with a dart from the right faceoff circle past Subban. A minute later, T.J. Oshie would send Subban to the showers with his 16th goal and a 3-1 lead.

Three goals on three shots on Subban in four minutes and twenty-one seconds.

“Completely psyched out,” Kluzak said later about Subban at that point.

Rask stopped the bleeding — for most of the remainder of the period.

Jordan Caron went toe-to-toe with Lindbolm at 6:44, hoping to ignite a Bruins comeback. Unfortunately, he also took two minutes for roughing, and the talented sniper, Vladimir Tarasenko, nailed his 30th of the season past Rask on the power play just 40 seconds later.

A Boston power play – third of the game to that point – went for naught to end the period.

“Great big bucket of ‘ick,’” NESN analyst Dale Arnold said to sum up the second period.

Ironically, Boston outshot St. Louis by a 2-1 margin entering the third period, and 27-15 overall.

The final 20 minutes were a snoozer for Boston, while Tarasenko blew one past Rask for his second of the game and 31^st overall at 11:45 in the 5-1 final.

The Bruins lost David Krejci for the rest of the game in a neutral-zone hit on Alex Steen early in the second period.

“Tough way to start your NHL career, but sometimes you just gotta flush it,” NESN’s Jack Edwards said about the 21-year-old Subban’s baptism under fire.

The Bruins have to find an immediate solution to their game to avoid their season being flushed.

“Times are not so good for the Boston Bruins,” Edwards said to begin the third period. “The next two weeks will be instrumental in the re-tooling of the Boston Bruins,” he added at the final horn with the trade deadline looming March 2.

“What doesn’t kill you will make you stronger,” Julien said postgame about his words to Subban after.

Words that now apply across the entire roster – and organization.

If Florida takes out Ottawa Saturday night, the Bruins will be outside the playoff picture when they face off Sunday against Chicago. Hard to accept that scenario, given these two battled for all the marbles less than two years ago in the Stanley Cup Final – and Boston won the President’s Trophy as the best team in the regular season less than one year ago.