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MLB Handicapping: Seattle Mariners Have Been an Over Bettor’s Dream


If you are wondering what an “over” MLB team looks like, look no further than the Seattle Mariners. Nearly 75 percent of Seattle’s games thus far have gone over the total (35-12-2 O/U). As with any early season outlier statistic, it deserves some investigation as to why and whether or not bettors can expect it to continue.

When bettors think “overs” it’s often because of a weak starting staff, gas can bullpen, and/or potent offense. The Mariners have a lot of those traits but they’ve also shown to be MLB’s worst defensive team. According to FanGraphs, Seattle’s team defensive rating is currently -33.3. To compare, the second worst rate is the Chicago White Sox at -16.0. Should Seattle’s defensive ineptitude continue, it would rank as one of the worst units in MLB history.

James Paxton’s departure was a massive blow to the starting rotation. Seattle’s starting staff ranks dead last in MLB in strikeout rate at 6.96 per nine innings. With a slew of pitch-to-contact arms and a horrific defense, it’s no wonder “overs” are cashing at a high rate. And while the defense’s lack of production has a chance to eventually regress towards the mean, the rotation doesn’t have much of any upside. Marco Gonzales is on borrowed time (3.65 ERA vs. 4.98 xFIP), Felix Hernandez (6.52 ERA) appears past the point of no return, Wade LeBlanc and Eric Swanson have combined for a mid-7 ERA over 10 starts, and Mike Leake simply isn’t capable of stringing together multiple dominant starts. Newly acquired Yusei Kikuchi has shown flashes (3.43 ERA) but the verdict is still out on whether or not he can handle the league a second and third time through.

Seattle’s bullpen hasn’t been as bad is its overall statistics (5.50 ERA and -0.5 WAR) thanks to some blow ups by a number of its fringe arms. The core group of Roenis Elias, Connor Sadzeck, Cory Gearrin and Brandon Brennan has performed well but everyone but Elias has outpitched their peripherals thus far. Overall, it’s a unit that is projected to finish in the bottom quarter of the league.

Offensively is where it gets interesting. The Mariners are currently fifth in MLB at 5.3 runs per game but the production has regressed in a big way after an incredibly hot start to the season. Over their last 21 games (6-15) the Mariners are averaging a more pedestrian 3.8 runs per game. They still lead the league in home runs (90) but sustainability remains a question as aging Edwin Encarnacion and Jay Bruce (25 home runs combined) will inevitably miss time due to injury.

Now, let’s take a look at how the betting markets have adjusted to Seattle’s early season “over” ways.

Home O/U: 16-7-1
Home Avg. Total: 8.6
Road O/U: 19-5-1
Road Avg. Total: 9.3

Home O/U: 37-42-2
Home Avg. Total: 8.1
Road O/U: 41-38-1
Road Avg. Total: 8.7

You can see that the average total, both home and away, is a half run higher than what we saw in 2018.

Seattle is no doubt a much different team that what we saw last year. Paxton performed at a near ace-level. Reliever Edwin Diaz, who is now with the Mets, posted a 3.5 WAR. Jean Segura and Mike Zunino were above average defenders but are no longer with the team. And Kyle Seager, another plus defender, is still rehabbing but expected to return soon.

In the end, oddsmakers have made an adjustment but even if the offense performs at a league-average level the rest of the way, the starting staff, bullpen, and defense are unlikely to endure significant improvements. We probably won’t seen as many 8 and 8.5’s as we did earlier this season but betting Seattle over the total should remain on your radar.