Over/Under Win Total Bets for 2018: Fading the Humidor, Tigers & Padres

Over the last 18 years, I've come out ahead. My overall record is 44 for 79 (with one push) for 55.7 percent. My best bet each season is 15-13 (I had multiple biggest bets some years). I'm a little better on bets of $100 or more (I vary my bet size to emphasize how strongly I feel about the pick) where I'm 12-9. I'm most impressive on a weighted or cash basis, where I've been correct 60.1 percent of the time ($2,900 in winning bets, $1,925 in losers - not factoring in the vig).

However, I've been in a big slump going 1-7 the past two years. When I started writing this story in 2000 my idea was to see if you could be successful on these bets by sticking to some basic principals similar to investing in the stock market. While all kinds of new data has emerged and the stock market has seen some changes, the basic principles of Value Investing still work. Similarly, could we take basic sabrmetrical principles and apply them to the market and consistently win? As a result I've hesitated to add new metrics by diving into batted-ball data, Statcast metrics and WAR calculations. But a few losing years and I'm certainly questioning if the times have caught up with me.

Certainly the sportsbooks have adapted as the betting lines have conformed more with the popular projection systems from Baseball Prospectus' PECTOA, Fangraphs and others. There's also much more media coverage of the win total lines as I was one of the few writing about them in 2000. Among the other great reads on the subject his year are Jonah Keri at CBSSports.com, Aaron Gleeman at Baseball Prospectus, the Joe Sheehan newsletter and the Gleeman and the Geek podcast.

But taking a step back, I still believe if you find the outliers from the basic principles you can make money. Let's try to reverse my recent trend this year:

For this exercise, I'm using odds from VSIN.com which I grabbed on March 20.

When I look at a upcoming baseball season, there are eight methods I use to judge which teams might be a good bet: Three are statistical, four are observations I've had watching the bookies set season-long lines for MLB and other sports and lately I've thrown in a wild card pick with no particular theoretical basis. Here's the breakdown on these theories and the teams I decided to actually wager on.

The Johnson Effect

The Johnson Effect argues that a team that scores more runs or allows fewer runs than most statistical formulas would suggest, is bound to regress the next season. For example, if one team scores more runs than sabrmetrical formulas such as Runs Created or OPS might suggest, then it will score less the next season. The theory works based on the fact that sometimes a team has more success than it should just based on pure luck. A bad bounce here, a fluke play here - they can add up in one season and make a team look more powerful than it should be.

My favorite type of statistic for this analysis is a tool called the Pythagorean Theory. You probably learned the Pythagorean theory in trigonometry, but in baseball it means that the ratio of a team's wins and losses will be similar to the relationship between the square of its runs scored and the square of its runs allowed. If the runs a team scores and gives up in any given season don't translate into the expected win total from the Pythagorean Theory, that means something odd took place that should turn around next season.

Using the Johnson Effect and applying the Pythagorean Theory, who looks like they'll rebound in 2018? Here are the top teams that should have seen more or less wins based on their 2017 runs allowed/created than they actually tallied:

San Diego Padres +12
Kansas City Royals +8
Philadelphia Phillies -6
Cleveland Indians -6
New York Yankees -9

I usually like to look for teams that have a differential of ten or more games. It's a bit shocking to see that the 71-win Padres should have been a 59-win team based on their runs scored and allowed. A team that plays ten games better than their Pythagorean projection typically takes a step back the next season. Since 2001, teams that finished 10 or more games better than their Pythagorean projection declined an average of 13.1 games the next season. And in fact, all seven teams declined the next season. It may be a small sample size and the San Diego roster may be very different this season than last year (most notably their entire starting rotation and the addition of Eric Hosmer), but I don't think anyone thinks the Padres will make a big leap this season. They may need to take a step back before their wave of minor league talent that's close to the majors kicks in. As a result I'll bet $25 the Padres don't win 72.5 games.

The Plexiglas Principle

This theory says that any team that improves dramatically in one season is likely to decline the next season.

What teams made such dramatic moves from 2016 to 2017?

Minnesota Twins +26
Arizona Diamondbacks +24
Houston Astros +17

Since 1970, teams that have improved by 19 or more games declined by 7.1 wins the following season. The decline is even sharper for teams who have improved by 24 or more games (-11.6 games) and 26 games or more (-9.67). The Diamondbacks are expected to decline by eight games in 2018 and the Twins are expected to decline by just two games according to the sportsbooks. Both appear to be solid bets on this principle alone. Arizona in particular looks appealing as their performance may be susceptible to a lot of variance. Chase Field is installing a humidor this season in an effort to help pitchers and limit offense in what had become a hitter's park. Will this adjustment be best for a roster that was fifth in the NL in home runs? Even if that figure is inflated by the home park, will their hitters adjust changing their mindset when fly balls die on the warning track? And what if the humidor effect is sharper than many expect (which Derek Carty explains in this great Twitter thread). Plus with losing J.D. Martinez in free agency and Zach Greinke having outings with a dramatic drop in velocity, it's not hard to see the team taking a step back. Add it all up and I'll bet $100 that Arizona wins fewer than 85 games.

The Twins are a tougher case. Their decline to 59 wins in 2016 from 83 wins in 2015 seemed like a fluke - so much so that the sportsbooks didn't price in much of a rebound. But I didn't make a bet on Minnesota because, to quote myself, "Still, I may make this bet if I wasn't a Twins fan and fearful of rose-colored glasses." And that may be the case here as well. On it's face the Twins had a lot go right last year improving from what likely should have been a high-70s win team to 83 wins and a playoff appearance. They became the first 100-loss team to make the playoffs the following season. A number of young players improved dramatically (Eddie Rosario, Jose Berrios, Byron Buxton, Miguel Sano). They seem like a team set to decline. However, the Twins improved their roster in the offseason, especially their depth, by signing Logan Morrison, Lance Lynn and Jake Odorizzi at bargain deals. Still, already they've had some tough breaks with Ervin Santana suffering a finger injury that could easily linger longer than his projected early May return date, starting shortstop Jorge Polanco was suspended 80 games for a PED violation and Sano faces a potential suspension for a 2015 sexual assault allegation. A bet against them winning 83.5 games seems like the right call, but like last year I'll sheepishly pass.

The Reverse Plexiglas Principle

When a team has consistently been a winner and then experiences a sudden drop off, there is a strong likelihood that its win total will rebound. Or at least that's my theory. I haven't had a lot of success with this bet (1 for 4).

Here are the teams that declined the most in 2016:

Baltimore Orioles -14
New York Mets -17
Texas Rangers -17
Detroit Tigers -22
San Francisco Giants -23

The Giants look like the easy bounceback candidate. San Francisco's season was torpedoed when Madison Bumgarner suffered a shoulder injury in a dirt bike accident in April. San Francisco's season went off the rails as their offense also finished second to last in the NL in runs scored per game. The Giants made moves to improve their offense by trading for Evan Longoria and Andrew McCutchen. The sportsbooks, however, see a bounceback and have them improving by 19 games to 83 wins. That's likely too much as the Giants, despite their three World Series titles this decade, have won over 90 games just twice this decade. They won 87, 84 and 88 games the prior three seasons. In fact, I may take the under as their team is getting older without much of a farm system and a decline of the Posey-era Giants seems more likely.

The next thing I look at is what teams the bookies think will have the biggest improvement or decline.

The Bottom Feeder Bet

This is totally from a non-scientific study of watching the bookies set the lines on expected wins over the years. People tend to care less about the bad teams in any sport, so the line is set a bit lower to entice folks to bet on these doormats. I've won 6 of 9 bets since 2001 with this theory. Let's look at this year's candidates.

Miami Marlins 64
Detroit Tigers 66.5
Kansas City Royals 69
Chicago White Sox 71
Baltimore Orioles 71.5
San Diego Padres 72.5

Of these teams, only the White Sox and maybe the Padres would appear to have a trajectory that's headed upward in the near term. The Tigers and Royals still appear set to get worse before they get better. In fact, the Tigers may be the worst team of the next five years with a thin farm system, no major league stars and new ownership that may not invest in the team as before. I think the Orioles may be a little low but their team could collapse given the age of their stars and terrible starting pitching (even with the late signing of Alex Cobb). Still, I don't see a team that really fits the profile. I usually want a team out of this group that's young and moving upward. Perhaps the White Sox fit that bill, but it's the first year of their rebuild. They'll probably be in this group next year and then I'll take them.

The Book's Biggest Movers

Miami Marlins -13
Kansas City Royals -11
Los Angeles Dodgers -8.5
Arizona Diamondbacks -8
Philadelphia Phillies +12
New York Mets +12.5
San Francisco Giants +19

I've already talked about the Giants and Diamondbacks. Miami's decline makes sense after its post-sale teardown. If anything I may take the under as it may sell off more parts, but 64 wins is pretty low. Still, nothing from this group stands out.

The Book's Non Movers

Baltimore Orioles -2
Tampa Bay Rays -2
Minnesota Twins -2
Boston Red Sox -2
Milwaukee Brewers -1.5
San Diego Padres -1
Pittsburgh Pirates -1
Texas Rangers -1
Oakland Athletics 0
Chicago White Sox +1
Chicago Cubs +1
St. Louis Cardinals +3
New York Yankees +3
Detroit Tigers +3.5
Atlanta Braves +3.5
Seattle Mariners +3.5

Basically, the sportsbooks have a lot of teams they think will stay the same. It seemed to be the same last year when the sportsbooks projected 19 teams within 3.5 games of their previous year's record. Only 7 of those 19 teams finished with 3.5 games of their projection. Similarly, 15 teams are projected to be within 3.5 games of their 2017 record.

One team that stands out for me on this list is the Tigers. The Tigers may be the worst team in baseball this season outside of Miami. Last season they got a little more than half a season of Justin Verlander. This year they may trade off veterans if they are healthy (Miguel Cabrera and Victor Martinez) and don't have viable replacements if they are hurt. Their starting pitching staff is poor with over-the-hill Jordan Zimmerman and Francisco Lirano in the No. 3 and No. 4 spots. Their minor league system is barren and their best prospects are in the low minor. They also hired a manager in Ron Gardenhire who may not be a great fit for a rebuilding effort. In short, I just don't see how they can be better this season. I'm not usually taking the under on a team projected for less than 70 wins, but I'll bet $50 Detroit wins fewer than 66.5 games.

Wild Card

I've done a wild card pick five of the last seven years based on hunches or other statistical trends. I'm 2-3. I don't have a bet in this category for 2018. I do have a theory, however. With so many teams declining to spend in the free agent market and so many teams seen "tanking" as they rebuild and try to obtain higher draft picks, I think we'll see extremes at each end of the standings.

It wouldn't surprise me if the top 3 teams in the AL (the Astros, Indians and Yankees are all loaded), for example, had more then 300 combined wins. Or if a team had more than 110 wins. Conversley, I wouldn't be surprised to see a team with more than 105 losses (looking at you Detroit), I couldn't find a bet to capitalize on this theory, but maybe it's out there.

To recap, here are my bets for 2018.

One note: My bets/track record doesn't try to account for the variations in extra juice you need to pay. Most lines are -110, meaning the sportsbook takes about five percent on each bet. The "Vig" tends to be higher on these bets than for single games. Sometimes the vig can vary widely, such as when 2016 Texas Rangers under of 83.5 wins was at -140 (the under was +110). It's another method for the bookmakers to alter how the money is coming in on each side so it gets to their comfort level. Or it's a way to change the odds without moving the win total.

If you are making a lot of bets, this is a serious factor in the math. But I don't bother to take that into account because I'm more focused on the overall wins number for a team perspective. Plus, I forget to keep track of the Vig in early years.

I vary the dollar amounts below as a way to show how confident I am in the bet (the $300 bet on the 2004 Royals is my all-time high), so there are some holes in the math if you added in all the varying vigs.

And why should you care what I think? I've made money nine of the past 16 years (with one push). Here's the breakdown: