YOU SAID:

Just saw the headless horseman, but he was on foot running after his horse

INTO JAPANESE

ただ頭のない騎手を見たが、彼は馬の後を走って歩いていた

BACK INTO ENGLISH

I just saw a headless jockey but he was running after the horse and walking

INTO JAPANESE

私はちょうど頭のない騎手を見たが、彼は馬の後を走って歩いていた

BACK INTO ENGLISH

I just saw a headless jockey but he was running after the horse and walking