Does Safeco Field Make the Mariners Worse?

The Mariners have been an offensively inept team for years. This has been readily apparent over the last two years when the Mariners broke several modern day records for offensive futility. These years of failure have driven many fans to look outside of the obvious for explanations. One of the theories often proposed is that Safeco Field is just too hard to hit in. The argument is that the field’s dimensions prevent the Mariners from scoring runs and winning games. The field somehow turns good players into bad ones. This theory is popular and it intrigues me. So, I did some research to try and answer the question, does Safeco hurt the Mariners ability to win games?

First, I wanted to validate that Safeco does in fact have a negative impact on offense as compared to the rest of the league. To do this I looked at the HR hit and runs score by Mariners opponents at Safeco and compared them to half the league average. I looked at the Mariners opponents because that data won’t be tainted be the skill level of the Mariners offensive players. This method does leave a potential error for the quality of Mariners pitchers, but it should still give us a good approximation. I used half the league average because each team plays half their games on the road. Although some team will hit more HR at home and others on the road the differences should average themselves out or at least provide a good approximation of the average road HR per team.

Comparing Opponent Runs and HR both at Home and Away to half the league average I created Chart 1 and Chart 2. The Mariners Home Opponents have been consistently below half the league average for both Runs and HR. Only once in the 12 year history of Safeco have visiting opponents scored more runs than half the league average. This was 2007. For HR, opponents have bested half the league average in only 3 of the last 12 years. One of these years, 2004, the Mariners pitchers were particularly bad and not just at Safeco. They gave up 108 HR at Safeco but also got killed on the road giving up 104 dingers. The data in Charts 1 and 2 confirms that Safeco does in fact suppress offense.

Now that it can safely be said Safeco does inhibit offense, I wanted to see if Safeco was a primary reason for the Mariners offense blight. I looked at the number of HR hit by the Mariners on the road and the number of runs scored on the road and compared it to half the league average number of HR per team and runs per team. This approach should show if the team is bad at offense everywhere or just at home. Charts 3 and 4 show this data.

What I found is that the Mariners have been consistently below the league average in both categories. Additionally the number of HR they hit and the number of runs they score has been decreasing at a rate faster than the rest of the league. The Mariners are struggling on the road offensively just as much as they are at home. If it was truly just Safeco bringing down the Mariners offense we would expect to see the Mariners HR and Run totals more closely match the league averages on the road. This is because on the road Safeco and it real or imagined effects cannot impact the Mariners. Instead this data points to Safeco not being the culprit for years of miserable offense.

However, there is another theory about how the offensive doldrums of Safeco Field harm the Mariners offense on the road as well as at home. This theory argues that Mariner players struggle so much at home that their confidence is completely shot after each home stand. This lack of confidence then acts to impede these same players in the other half of their games away from Safeco. Basically Safeco is playing brain games with our batters. They are so distraught after failing repeatedly at home that they can’t ever get it going on the road. However, without some sort of insight into the psyche of each player this theory is very hard to prove or disprove and sense I am not a psychologist and I won’t pretend to be one, I am not even going to try. Let’s just leave this theory alone recognizing that it does exist and probably does contribute as a secondary effect

If my limited and non-comprehensive research shows anything it is that the pitcher friendly confines of Safeco field limit offense in Mariners Home games and that is all. Using runs and HR as a measuring stick, there appears to be no proof that Safeco has some kind of mystical power to during otherwise good players into AAA hacks. Mariner’s players over the last several years have failed on the road just as poorly as they have at home. The problem is not with the stadium but with the players.