NHL weeknight betting guide: True moneylines for March 21-24

The Philadelphia Flyers made pre-trade deadline headlines when they dealt Claude Giroux to the Florida Panthers this past Saturday. This created what I would call a "two-way tweak" to the win probability for the Flyers' game against the New York Islanders on Sunday afternoon.

The Islanders playing on the second of back-to-back days creates a drop in their win probability, as it does for any team in that spot. That amounts to about a 5% dip.

Going the opposite way, Philadelphia traded its captain! The more quantifiable issue is the Flyers are now without one of their best players. The second issue is a matter of morale. How much less likely are they to win based on how the dressing room feels about Giroux's departure, and how will it affect their play in the immediacy?

Giroux was held off the scoresheet and recorded a minus-one in 17:47 of ice time in a 5-4 win against the Nashville Predators on March 17. Philadelphia then held Giroux out of the lineup for the following night's 3-1 loss in Ottawa against the Senators.

Lined at 92.5 points before the season, the Flyers have disappointed this campaign, which is why they made Giroux available. It's also made them difficult to rate with such relatively optimistic priors. However, if you've consulted our weekly guide in this space, you'll have seen that Philadelphia has shown value as big underdogs but has been largely rated accurately in recent games against the Chicago Blackhawks, Montreal Canadiens, and the March 18 contest against the Senators.

Our collective antennae should have gone up when oddsmakers priced the Flyers just shy of +150 at home to the presumably tired Islanders on Sunday - in a game we would have lined Philly as slight favorites with Giroux playing.

The Flyers could be had for +140 on the moneyline. That's reflective of a team with a 41.7% chance to win the contest. That's considerably lower than the 53.9% chance we'd give them with Giroux in the lineup, even after accounting for a sportsbook's vig.

As an informed bettor in that situation, you have to decide whether Giroux is worth a double-digit percent downgrade. As a frame of reference, oddsmakers dropped the Maple Leafs' win probability by no more than 10% in the two games last week in which the MVP-favorite Auston Matthews was out due to suspension.

Believing Philadelphia's moneyline of +140 was an over-adjustment after trading Giroux would have landed you a valuable bet and a winning ticket with the Flyers edging the Isles 2-1.

The recipe

Before the 2021-22 campaign, we devised a three-part series on how to use the regular-season point-total market to create team ratings, how to interpret home-ice advantage, and then how to use those to create your own moneylines.

We made a small adjustment to our formula a couple of weeks ago, moving this season's on-ice predictive metrics to 75% of our total rating. While our ratings are weighted to this season, basing 25% of the ratings on preseason "priors" allows us to emphasize team metrics without going all-in on what's happened this campaign. That's important because this season is still a relatively small sample size that includes some tainted results from when COVID-19 ravaged lineups.

The stabilization of rosters at the All-Star break has meant that underdogs, or favorites that aren't favored by enough, are now priced that way due to less quantifiable reasons, like public perception or short-term variance.

The cheat sheet

What follows is my fair price on the matchups (true moneyline) and the moneyline price I would need to bet either side. I just need a 1% edge for a favorite if we're getting better than a fair price on the team more likely to win. For the underdog, I'll need 4% or better to make it a bet. On games I've projected to be a near coin flip, a 2.5% edge is enough to make it a worthwhile wager. I also have a 5% win probability consideration for a side playing in the second game of a back-to-back with travel and 3% for without travel.

Matt Russell is a betting writer for theScore. If there’s a bad beat to be had, Matt will find it. Find him on Twitter @mrussauthentic.