Monday MLB Betting Picks, Predictions: Marlins vs. Braves, Astros vs. Mariners (Sept. 21)

Monday Night Football is taking the brunt of the betting action throughout the day today, but there are still 11 baseball games getting underway to start the final week of the regular season.

Our experts have found value on two of those in particular, and they're both taking similar strategies to highlight respective starting-pitching edges.

Note: Odds as of 1 p.m. ET.

Advanced Stats Glossary

FIP or Fielding Independent Pitching measures what a pitcher’s ERA would look like if the pitcher experienced league-average defense and luck. xFIP is a regressed version of FIP that adjusts or “normalizes’ the home run component based on park factors.

wRC+ or Weighted Runs Created Plus takes the statistic Runs Created and adjusts that number to account for critical external factors — like ballpark or era. It’s adjusted, so a wRC+ of 100 is league average, and 150 would be 50 percent above league average.

wOBA or Weighted On-Base Average is a catch-all hitting metric with more predictive value than on-base percentage. An average MLB hitter can be expected to post a .320 wOBA. xwOBA is a regressed version of wOBA that accounts for variables like park factors.

Sean Zerillo: Marlins F5 Moneyline (+128), F5 Spread (+0.5, +100) vs. Braves

• Odds available at DraftKings [Bet Now]
• First pitch: 7:10 p.m. ET

Two months ago, had you told me that I would be betting on the Miami Marlins more consistently than any other team in sports, I would have demanded that you take away all of my electronic devices; someone behaving in such a way obviously could not be of sound mind.

But here we are in late September, and at 28-25, the tropical fish have an 84% chance of making the playoffs. Their magic number is down to six games.

The Marlins are able to keep themselves in virtually every contest with strong starting pitching, and rookie southpaw Trevor Rogers has impressed over his first five MLB starts, recording a 29:10 strikeout-to-walk ratio in 21 innings pitched.

The 22-year-old former first-round pick offers a high-spin (82nd percentile) four-seam fastball (93-94 mph, 62% usage) paired with a solid changeup (84 mph, 18.5%) and slider (81 mph, 19.5%). Rogers has both gotten ahead in the count (62% F-Strike) and managed to get whiffs (12.5% swinging-strike rate) with all three of his offerings, but the changeup is likely Rogers’ best pitch:

Despite a 6.00 ERA, Rogers has posted a 3.13 expected ERA (xERA) in five turns through the rotation, and he’ll get a decent matchup on Monday against a Braves offense that ranks 21st in MLB with a 96 wRC+ against left-handed pitching this season.

Braves starter, rookie righty Huascar Ynoa, has been far from impressive in his young MLB career, allowing 17 runs and 13 walks (against 19 strikeouts) in 21.1 innings pitched. Ynoa is more of a two-pitch pitcher (>90% combined fastball/slider usage), and I see him as a much more effective bullpen arm, rather than a starting pitcher, both presently and long term.

I project the Marlins at 55% in the first five innings (F5) and at 45.8% for the full game on Monday. I have one unit on their full-game moneyline, which I would play down to +135, but I also split a unit between their F5 moneyline (play down to -105) and F5 spread (+0.5 runs, play to -120) — so I am heavily invested in the fighting fish yet again.

BJ Cunningham: Mariners F5 Moneyline (+125) vs. Astros

• Odds available at DraftKings [Bet Now]
• First pitch: 9:45 p.m. ET

Seattle lefty Marco Gonzales is having one the best seasons of his career, and the reason for that has been his command. He has one of the lowest WHIPs in baseball at 0.90, mostly due to the fact that he has walked only five batters in 56.1 innings. His sinker has been fantastic so far this season, allowing only .189 wOBA on it. His secondary pitches have also been really effective, collectively allowing only .241 average to opponents. The Astros have been horrible offensively as of late, so Gonzales has a good matchup on Monday night.

Houston has struggled offensively, accumulating a .309 wOBA and 98 wRC+. Those struggles have never been more apparent than in the last two weeks, as the Astros have only a .247 wOBA and 55 wRC+, which is the worst mark in baseball over that time span. In fact, George Springer is the only Astro with a wOBA over .320.

Lance McCullers missed all of 2019 due to Tommy John surgery, and it took him a while to find his command again. He's lowered his xFIP all the way down to 3.94 but is seemingly still having issues with his sinker and curveball.
Both pitches are allowing over a .320 wOBA to opponents, and his sinker is generating a whiff rate of only 12.1%. His changeup has by far been his best pitch, allowing only a .232 average to opponents.

The Mariners have been below average offensively this season, checking in with a .303 wOBA and 94 wRC+. Seattle started out as one of the worst offenses in baseball but has turned things on in the second half of the season, hitting for the 16th best wOBA in baseball compared to being in the bottom of five in the first half of the season.

The Mariners have the worst bullpen in all of baseball with a 5.01 xFIP. They traded away their best relievers at the deadline, and it's been a wasteland ever since. The Astros have improved from their early-season struggles and now have the 14th-best bullpen in baseball. So, Houston will have the advantage in the later innings during this series.

Given how good Gonzales has been, I think the Mariners are undervalued in this game. However, since they have the worst bullpen in baseball, I am going to avoid that mismatch tonight. Therefore, I am going to back Seattle for the first five innings at +125.