With a slew of "openers" and young pitchers without much data, Monday is a lighter slate for the first inning bets.
Be sure to read the explanation on the Mariners vs. Athletics game, as a couple of different options have nearly identical value, with it coming down to risk tolerance as to which one you choose.
The Model
The process is relatively simple. First, I start by assuming that the full game (implied) run totals for either team are roughly efficient. As mentioned above, that tends to be the case more often than not. This saves me the trouble of trying to predict the total runs scored in the game — and allows me to focus strictly on the "when" rather than "how many."
Next, I built a database of pitchers performance the first time through the order, relative to their overall stats. Since the latter is presumably baked into the full game total, I wanted to figure out if those runs are more likely to come early or late. Most — but not all — MLB starters do somewhat better early in games, but with some variance in just how much. The model uses xFIP (expected Fielding Independent Pitching) as the ERA predictor of choice.
That's only half of the equation, though, with the offenses making up the other half. To do this, I looked at what percentage of a team's total runs is produced by the top three batters in the lineup. While a first inning run scored, by definition, needs at least four hitters to come to the plate, one of the first three has to actually score it. The metric of choice here is wRC+, based on the projected lineup for the day from each team.
This is a bit of a tradeoff, as lineups (and run totals) can shift throughout the day, especially if significant contributors miss time. However, in my experience the inefficiency of the morning lines more than makes up for the leakage in the model. With that said, exercise caution if, say, Mike Trout is listed as questionable for the nights game.
The Picks
With all of the picks below, I'll include the pick, the best line and the threshold I'd bet it to. These will go up in the morning, so if any major news breaks between publishing and when you read it, be sure to consider that.
Infrequently, rather than betting on the traditional YRFI/NRFI, the pick will be on one team or the other specifically to score a run, which as of this writing is only a betting option at DraftKings. Since the model handles each team individually, sometimes one team is projecting for a greater proportion of the "run equity" in the first inning than the betting lines are accounting for.
NRFI Odds, Picks for Monday, May 22
Philadelphia Phillies vs. ArizonaDiamondbacks NRFI: This is another example of a game where only one team poses much of a threat to score, in this case the Phillies. That makes it a prime candidate for a single team hedge on Philadelphia at +170 on DraftKings, but the overall numbers show the NRFI as a far higher EV bet.
Kansas City Royals vs. Detroit Tigers YRFI: While these aren't great offenses (to put it mildly) these also aren't great pitchers, which is reflected in the 8.5-run game line that's juiced to the over. Both teams get a reasonable proportion of their offense from the top of the lineup (especially the Royals), making it more likely than not that some of the 8.5 implied runs happen in the first inning.
Milwaukee Brewers vs. Houston Astros YRFI: This game features much better pitching than the Tigers/Royals game, but also somewhat better hitting overall. More importantly, the Astros rank third in proportion of their scoring produced by the first three hitters. I have this one projected at slightly over 50%, so getting +110 odds is a solid bet — but betting half of your usual unit makes sense too, since it's close to a coin-flip.
Seattle Mariners vs. Oakland Athletics YRFI: The Mariners make up the bulk of the run scoring equity here, but unfortunately the price on their team-specific YRFI line reflects that as well, at +215 on DraftKings. Based on my model, I'm showing similar value on the game line at slightly plus-money on FanDuel. Either bet is a good one today, so it comes down to your risk tolerance. The full-game YRFI is more likely to win, but the payouts are better on Seattle specifically.
