101 Making your own line

MLB Handicapping 101

Step #1 Make your own line

It is IMPERATIVE to make your own line when handicapping sports. It is even more so in MLB because the differentiator is usually how to evaluate pitchers, not teams. There are many sports where all that is necessary is team evaluation where a spread is involved. MLB is different. The team part is relative to the other sports but knowing the pitchers is crucial.

I would like to say I have the very best approach but it is not mine at all. I stole and refined it. I use a 3-step method 1^st published by Joe Peta in the book Trading Bases. It is a financial world calculation to get the team evaluations, then a starting pitcher evaluation, and finally a home team edge. Joe was originally a financial trader on Wall St. He was hit by a car and spent a summer away, thus focusing his energy and thoughts on baseball. Let’s get into his model so you can make your own lines that are what I consider the “True” line. A true line is where there is no other influence. A sportsbook will make their line with influence on where they want you to wager or protect where they do not want wagers.  A true line is the most accurate of the teams and players and often will expose the line of the sportsbook. I will share an example from the MLB 2019 playoffs shortly.

We need a team evaluation to get the basis for our line. Based on my own research over the years, it is best to use the Sabermetric predictions and not the actual results. Over the course of the season, these will mirror each other, but especially the first half of the season, you will see some variance in team strength between these predicted results and the sportsbook. Don’t fear that. We want that variance as that will soon be one of our edges over the sportsbook! Team evaluation is based on FanGraphs Projected Standings winning percentage for each team. For the example I am going to provide, STL @ ATL 10/3 2019 Mikolas vs Keuchel, we need the winning percentage of each team. STL was .537 and STL was .556. Based on these winning percentages, we can formulate each team winning probability. That requires a formula.

                Formula for STL winning probability: (STL*(1-ATL)/((STL*(1-ATL)+(ATL(*1-STL)

                Formula for ATL winning probability: (ATL*(1-STL)/((STL*(1-ATL)+(ATL(*1-STL)

The result will look like this. STL win probability is 48.08% and ATL is 51.92%. We will adjust these later. The line for this game was ATL Keuchel -143 and a total of 7.5. Using an Odds converter, we can convert the win probability of 51.92% to a money line. In this case, it comes out to ATL -108. Right off the start, you can see where there is some value. We will adjust ATL up later due to their home field later.

Now we must properly evaluate the starting pitchers who will have the most impact on the line. This is the most important part of making the line accurate.  The way I do this is based on the WAR the pitcher has contributed to the staff. I total the staff WAR then divide the starting pitcher contribution to it, which then becomes the adjustment we must make to the team winning percentage. I use any pitchers that are projected to have started 5 games. Again, we are using the projected results. The purpose of the projected results is to eliminate human variance. We can get enamored in the “what we have last seen” syndrome and often over or under evaluate a pitcher by his true results. WAR is a statistic that measures a player's contribution to wins so it fits right into this extremely well. In this case, STL has 12.2 WAR and ATL 12.3 WAR. Mikolas has 2.8 WAR and Keuchel 1.2 WAR. We are now going to add or in some cases subtract the value of a starting pitcher to the team winning percentage. That requires another formula.

                Formula for Mikolas: (((2.8*5)-12.2)/162)+.537

                Formula for Keuchel: (((1.2*5)-12.3)/162+.556

The results are a new winning percentage of .548 for STL and .517 for ATL with new winning probabilities of STL 53.11% and ATL 46.89%. Now we are seeing the true value of evaluating pitchers! We now have STL as the favorite!

We now must adjust for home field. That adjust is a formula where the home team gets 2.75% added to their win probability. That is worth nearly 15 on the money line and is an adjustment I have made as Joe Peta’s version was too low.

Now we have completed analysis where ATL is 49.64%-win probability and STL is 50.36%. The true line should be STL -101 and the sportsbook line is ATL -143! We can bet on STL +123 at a tremendous value! The outcome in this game was STL 7 ATL6. Winner!

My spreadsheet does all the math for me and presents it like this:

I do this for every single game. It gives me a direction to look and prepare for. I then do more matchup analysis to either support this line or to find flaws. The more support to it the bigger I will wager.