On the ball and On the job

On the job and on the ball are semantically related in alert topic. In some cases you can use "On the job" instead the phrase "On the ball" as an adverb or an adjective, when it comes to topics like paying attention.

On the job adjective - Actively engaged in paid work.

On the ball and on the job are semantically related in alert topic. You can use "On the ball" instead the phrase "On the job" as an adjective or an adverb, if it concerns topics such as attentive, careful, on the lookout, concentrating.