Foot won't stay closed

I’ve noticed that my foot lands slightly open now and I think I am losing some power because of it. It doesn’t land open much but It’s enough that I can feel it land open. In practice it doesn’t do this it does it during games however and thats what counts. So what are some suggestions on how to keep my foot from landing open when I pitch?

Tough to say what the cause is without seeing you pitch. A posture or balance issue could cause it. So could a timing issue or front-side stability issue.