The Calgary Flames are in the middle of a hopeful turnaround to their season. Much to everyone’s pleasure, Geoff Ward has began his tenure as the interim head coach with a winning streak.

The Flames have played largely mediocre hockey through the first third of the season, and their record shows it. With a 14-12-4 record, they sit sixth in the Pacific Division and 11th in the Western Conference. They’ve got work to do if they want to defend their regular season title from last year. Despite their standings, they’re only six points out of first in the Pacific and 10 points out of first in the West.

It’s Rittich’s turn

One of the bigger stories going into the season were expectations of David Rittich. He was arguably one of the best goaltenders in the league last season prior to his injury. He raked in the wins and played a large role in the Flames’ success, despite being a backup behind Mike Smith. Boasting a personal record of 27-9-5 last season, Rittich played fantastic hockey beyond anyone’s expectations.

This season, Rittich received the reins as the starter, and has been relied on night in and night out to backstop the Flames. Facing one of the heaviest work loads in the league, he currently has a weaker record of 13-7-4. Despite the worse winning record, his numbers in net have been better. Below are selected stats at all strengths (data from Natural Stat Trick).

Season Games Played SV% GSAA 2018-19 45 .911 1.68 2019-20 24 .915 3.93

Rittich is currently playing very good hockey, so why has he lost almost as many times as he did last year in just a little over half the games? To explore this a bit more, I decided to take a look at expected goals (xG) against him, specifically using Natural Stat Trick’s xG model.

Expected Goals Against

There is a lot of information xG values can give, but one way to use it to evaluate goaltender performance is to take the difference between xG against and actual goals against. This can serve as a proxy to see whether a goaltender is making big time saves or if they’re letting in soft shots. If the differential is positive, then a goaltender is allowing less goals than expected, and likewise if the differential is negative, then a goaltender is allowing more goals than expected.

Plotting cumulative differentials game by game can highlight how a goaltender’s season progresses. In particular, I wanted to compare Rittich’s campaign last year versus what’s unfolded so far this year.

So let’s take a look at what’s been going on with Rittich. The chart includes all games played this season, including the latest game against the Buffalo Sabres.

Unsurprisingly, Rittich’s xGA-GA differential was very good last season at 5v5 score-and-venue adjusted (SVA). However, as the season went on, his all-situations performance plummeted. The Flames’ 21st ranked penalty kill (79.7%) played a large role in creating that big of a discrepancy between the game states, but Rittich’s injury probably had a large effect as well. He was simply much worse to end the season than he was to start.

However, this season shows a completely different story. Rittich’s differential has not been great in any game state. It’s trended down for much of the season. While he’s currently amidst a sizable bounce in the right direction, he’s still underwater.

Interestingly enough, Rittich’s differential is better at all-situations than it is at 5v5 SVA. The immediate stat to look at comes by revisiting the penalty kill. This year has been a complete turn around for the Flames, as they currently sit third in the league with a 85.6% efficiency. That definitely gives insight on the dramatic difference. The Flames are reliably killing off penalties, and that will go a long way being the league’s most penalised team.

What does this all mean

Rittich’s playing excellent hockey, so what is the value in comparing xG differentials? For starters, xG values are already cumulative based on summing the xG value of every shot faced. Being underwater in xG while posting above average goaltending likely all comes back to shot volume.

Simply put, Rittich’s facing more shots this season, and despite making more saves, he’s also forfeited more goals. When a team consistently gives up a high volume of shots, xGA follows suit. A goaltender would have to work harder to see positive differentials.

Currently, Rittich has faced 760 shots this season, more than any other goalie (Connor Hellebuyck comes in second with 724). Rittich’s facing an average of 31.2 shots per game, which is significantly more compared to last year, when it was at a much lower 27.3 shots per game.

It’s hard to put blame on David Rittich. While there may have been some gaffs a la being too aggressive playing the puck, Rittich’s truly been the team’s MVP this season. The Flames need to pay him back. Rittich can’t save every shot, but the Flames can certainly tighten up defensively.

Even if they can limit shots against back to the same level they were at last season, that’ll quickly add up. Anything to lighten Rittich’s work load is a positive. He’ll be called upon for many more times. A third of the way into the season, he’s far exceeded expectations.

Next steps

There’s much more hope for the Flames’ season being under Ward’s tutelage. There’s every reason to believe Ward is the right man for the job. On the ice, Rittich is earning top marks night in and night out, and the players in front of him need to help him out.

The Flames can turn things around. The western playoff race is as tight as it’s ever been—string together some more wins and the Flames are right back in the conversation for best in the west.

The game plan is simple. Limit shots against (especially the high-quality ones), play full sixty-minute games, and most importantly, do it for Big Save Dave.

All data courtesy of Natural Stat Trick. Charts made with R using “ggplot2“.