The struggles of the Mariners' offense at Safeco are on the mind of most every Seattle fan. The what, the sheer size of the offensive drop off, is disturbing; but it is the why that is more interesting. It is important to note that Safeco's bugaboo this season is not isolated to just Mariner hitters. Visiting hitters are also seeing a dramatic decrease in run scoring.
Ignoring that for the moment, I wanted to focus specifically on this fanpost and the first hypothesis contained therein, that the Mariners' approach is changing at home compared to on the road. It's a reasonable hypothesis. The Mariners are exhibiting a marked difference in walk and strikeout rates at home versus the road. Alas, proof required split plate discipline numbers to investigate. Those numbers are, to the fanpost's author, not publicly known. Lucky for y'all, I do have those numbers.
Welp. That is not data that supports the hypothesis. Those almost identical across the line. I went to the tenths place in the last column to illustrate just how close the rates stood at the time of writing.
It doesn't disprove the hypothesis mind you. Personally, I'd want to investigate splits by count and by pitch before I felt comfortable dismissing it completely. But, if there was a change in approach, and it were meaningful enough to cause a significant shift in results, I do expect that traces of it would appear in the overall look above.