First of all, I have no idea if it’s “base runner” and “base running” or if it’s “baserunner” and “baserunning.” I’ve seen it both ways, and I don’t know which is correct. The glossary on MLB.com lists the term as baserunner, one word. Merriam-Webster
I'm right there with you on "base running" vs "baserunning". When I was sports editor at 538, where we had a very exacting copy desk, they insisted on 2 words. But as a kid growing up consuming baseball material, I feel like I almost always saw it as 1 word. So that's what I go with at my Substack, though sometimes I also just like to fly in the face of AP Style for fun. ;)
I'm right there with you on "base running" vs "baserunning". When I was sports editor at 538, where we had a very exacting copy desk, they insisted on 2 words. But as a kid growing up consuming baseball material, I feel like I almost always saw it as 1 word. So that's what I go with at my Substack, though sometimes I also just like to fly in the face of AP Style for fun. ;)