On Saturday Vs On Saturdays

[patos32]

Thanks in advance.
What is the difference between On sturdays I play tennis and On Saturday I play tennis.
The difference is very subtle.
Please help me.

[riverkid]

Thanks in advance.
What is the difference between On sturdays I play tennis and On Saturday I play tennis.
The difference is very subtle.
Please help me.

With the limited context available here; with the plural 'Saturdays', the speaker is saying that every Saturday is for tennis, whereas the second sentence says this Saturday, I'm scheduled to play tennis.

That's why the present simple can be used here; a scheduled event. Not that it has to be used, it's just an option.

On Saturday, I'm playing tennis.

" ", I'm going to play tennis.

" ", I'll play tennis.