For the Toronto Maple Leafs and Ottawa Senators, 2013-14 marked a step backward. The Leafs missed the playoffs for the eighth time in nine seasons, while the Senators fail to make the cut for the third time in six seasons.

It wasn’t supposed to be like this. The Leafs were hoping to improve upon last season’s performance, where they ended a seven-season playoff drought, while the Senators entered this campaign considered by some observers a possible Stanley Cup contender.

The Senators got off to a poor start and spent the rest of the season playing catch-up, while the Leafs went through a rollercoaster of hot streaks and poor play before collapsing in a late-season swoon.

What steps can the Leafs and Senators take this summer to improve for next season?

What steps can the Leafs and Senators take this summer to improve for next season?

The Senators felt the absence of former captain Daniel Alfredsson more than they realized. New Senator Bobby Ryan didn’t click offfensively with center Jason Spezza. Goaltenders Craig Anderson and Robin Lehner didn’t play as well as in previous seasons. Several young Senators (Jared Cowen, Patrick Wiercioch, Colin Greening) failed to improve as hoped.

Injuries to several key players (Tyler Bozak, Dave Bolland, Joffrey Lupul, Jonathan Bernier) took its toll on the Leafs. Free agent signing David Clarkson failed to turn into the Wendel Clark clone the Toronto media envisioned him to be. They also lacked skill on their fourth line.

Both clubs, however, shared a fatal flaw this season. Defensively, they sucked.

While both clubs were among the top half of the league in goals-per game (Ottawa was 10th with 2.85, Toronto 13th with 2.75) and power-play percentage (the Leafs were fifth overall at 20.3 percent, the Senators 15th at 18.1), they were terrible on the penalty kill (the Senators were 23rd at 80.6 percent, the Leafs 28th at 78.2) and downright horrible in shots-against per game (Senators were 29th at 34.9, the Leafs 30th at 35.9).

As long as their respective goaltenders were playing well, it would mask the atrocious defensive play of both teams. When the goalies struggled or wore down from their heavy workloads, both clubs were in trouble.

The Senators can try to blame their woes as part of the rebuilding process, but that’s too easy. As Graeme Nichols of SenatorsExtra noted, the Senators didn’t suddenly become a lousy defensive team. They were also lousy last season. Superb goaltending masked the problem.

One positive for the Senators is that they’re a better puck possession team this season than the Leafs. If they can tighten up their defensive play without sacrificing too much of their offensive game, they should rebound next season.

The Leafs, on the other hand, have been openly skeptical of puck possession stats going back to the start of the season, when their inevitable collapse was foretold by those who follow hockey analytics.

While advanced stats like Corsi and Fenwick aren’t the end-all and be-all for assessing a team’s performance, they are invaluable in revealing a team’s strengths and weaknesses. The Leafs’ Corsi and Fenwick numbers are horrible this season. If GM Dave Nonis wasn’t convinced of the usefulness of advanced stats at the start of this season, he had better become a convert if he wants to properly address his club’s weaknesses prior to next season.

So where do both clubs go from here? Obviously they must both improve their defensive play. A significant reduction in the workload of their goaltenders will help avoid injuries and late-season meltdowns.

Given the Senators’ solid puck possession numbers, implementing a stronger defensive game without sacrificing too much of their offensive production should improve their overall performance next season.

When Senators GM Bryan Murray last month seemingly declined to give coach Paul MacLean a vote of confidence last month,  some wags wondered if last season’s NHL coach of the year could be fired. Unless MacLean is unwilling or unable to change, there’s no reason to replace him. Like his team, MacLean should be given the opportunity to learn and improve.

For the Leafs, however, more drastic measures could be needed. As the Globe and Mail’s James Mirtle observed, the Leafs did themselves no favors by replacing two of their best puck possession players last season (Clarke MacArthur and Mikhail Grabovski) with Dave Bolland and David Clarkson. Their lack of depth beyond their top two lines and the horrible team defense were significant factors in their late-season collapse.

The Leafs could try to address their roster depth issues, and likely will, but the biggest change must take place behind the bench. Either that, or the Leafs will have to completely overhaul their roster to find players who can fit into head coach Randy Carlyle’s system. That isn’t likely to happen. Unless Carlyle and his staff are willing to wholeheartedly change their system, they must be replaced.