— Another spring, another bitter — and some would say premature — end to the Washington Capitals’ season. The area’s most successful sports franchise lost Wednesday night in Game 4 of the National Hockey League’s best-of-seven Eastern Conference semifinals, 5-3, to the Tampa Bay Lightning. Thus the Capitals’ season ended with the ignominy of a sweep.

They’ve now been forced out of the postseason early four straight years, bewildering the team and leaving its red-clad horde of faithful fans — who’ve given the Capitals 106 consecutive sellouts at Verizon Center — almost bonkers with alternating bouts of frustration and despair.

The Lightning jumped out in front in the first period and the Capitals played from behind for most of the game. They trailed, 3-2, going into the third period, but goals by Marc-Andre Bergeron and Martin St. Louis put away the game — and the series. Defenseman John Carlson scored a late goal for the Capitals, but it was too little, too late.

“They had the upper hand on us all the time,” said veteran forward Mike Knuble in a nearly deserted Capitals locker room inside St. Pete Times Forum afterward. “I don’t think anyone saw this coming.”

The Capitals, coming off three straight seasons of playoff frustrations, thought they’d taken the steps necessary to achieve team owner Ted Leonsis’s stated goal: Nothing less than the Stanley Cup. They changed their system to a more defensive style, which was supposed to help them in postseason play. They righted themselves after a December slump, made key deals at the February trade deadline to add some veteran savvy to a young roster and won 12 games in March to help them win their fourth straight division title.

Yet none of that helped them avert a sweep by the Lightning, which is just the latest in a string of playoff frustrations for the Capitals.

“We did better than last year,” Carlson said. “But it’s a season thrown away, in my opinion.”

Now the Capitals’ front office has another summer in which to ponder its formula. There is no question some fans will call for the ouster of Coach Bruce Boudreau. Boudreau has taken this team to four straight Southeast Division titles – but he hasn’t gotten them beyond the second round of the playoffs, either.

Is the fault with Boudreau, or his team? That’s the question the front office will try to answer this summer. But Boudreau’s track record would indicate that for all the young talent on the roster, there is something missing from the Capitals’ locker room. Identifying that missing element will be General Manager George McPhee’s job; integrating it into the Capitals’ system will be Boudreau’s – more than likely.

Everyone in hockey has a nickname, and Boudreau’s has long been Gabby, for his talkative, affable nature. But he’s serious as a heart attack at this time of year. Asked Wednesday morning whether his job security hinged on the outcome of Game 4, he answered in much the same way he’s replied to similar queries all season, with a snort of derision.

“You guys keep asking me that,” he said caustically. “Is your job on the line? Then I don’t want to answer that.”

Leonsis and McPhee will be left to weigh this decision and a host of others, although close observers don’t expect Boudreau to be dismissed any time soon.

Yet something is lacking. The Capitals’ roster is young, and not by accident. After Leonsis acquired the team in 1999, he tried to buy high-priced – even over-priced – free agents to win quickly.

When that failed, Leonsis and McPhee decided to change tactics. So they dumped their high-priced stars and began to build a roster from the ground up, strengthening the farm system, increasing scouting, making wise draft choices — foremost among them forward Alex Ovechkin, one of the best hockey players in the world. The result: 11 first-round draft picks were on the Capitals’ season-opening roster.

The Capitals have marketed a core group of youngsters, but only Ovechkin and forward Nicklas Backstrom – both of whom have the equivalent of lifetime contracts – are untouchable.

Last year Washington had the best record in hockey – and lost in the first round to Montreal, the eighth seed, in seven games. Two years ago, the second-seeded Capitals needed seven games to get by the No. 7 New York Rangers before falling to the Pittsburgh Penguins, again in seven games. The year before that, the Caps went from last to first in their division but were eliminated in the first round of the playoffs by Philadelphia – again in seven games.

So this spring, when Washington needed a mere five games in which to dispatch the Rangers in the first round, it appeared its fortunes were finally turning, that a team as good as this one has been in the regular season might finally be able to extend its magic into May and perhaps even June, when the Stanley Cup is awarded. The Capitals have been in the NHL since 1974 and have gotten exactly one shot at that fabled trophy, in 1998, when they were swept by the Detroit Red Wings.

Asked if he expected wholesale changes to the roster next season, Knuble said, “I’m glad I don’t have to make that decision. That’s a real knee-jerk reaction. . . . Will there be changes? Of course. There will be different faces here next year. That’s a guarantee.”