The Chicago Blackhawks, a perennial Stanley Cup contender, are not living up to their usual lofty expectations this season. The team is last in the Central Division with a 22-17-6 record (50 points) with the possibility of losing goaltender Corey Crawford, out since Christmas with an ‘‘upper-body injury,’’ for the remainder of the season. Chicago’s captain, center Jonathan Toews, has just 31 points in 45 games, putting him on pace for the lowest scoring output of his career despite carrying the league’s top cap hit at $13.8 million. Two-time Norris Trophy winner Duncan Keith has yet to score a goal in 45 games this season. And, according to Hockey Reference’s playoff probabilities report, Chicago has a 67 percent chance of missing the playoffs for the first time since 2008. “That’s the result we gave ourselves,” center Tommy Wingels told Paul Skrbina of the Chicago Tribune. “That’s what we have to sit with. That’s on us.” The situation isn’t catastrophic yet — the Blackhawks are three points out of a wild-card spot — but there is a clear difference between this team and the title contenders from years past: the defense isn’t as good as it has been.