@vikbuddy and @hannahhive:
Common phrases are a different matter entirely. If the plagiarism check flags common phrases, then there's no action you should take against the user. However, if the user is pasting complete sentences from another source, then they are obligated to cite the source of their material.
Regarding sports content or anything else for that matter, again, it's the responsibility of the author to make sure the audience is aware that the information presented is not their own.