Usage patterns
〈事〉を後回しにするto put something off until later
Since I'm busy, I'll put off the small tasks for later.
〈事〉が後回しになるfor something to end up getting put off
An urgent job came in, so the cleaning ended up being put off.
〈事〉を後回しにして〈動詞〉to do something else while putting a task off
He's playing games while putting off his studying.