Question about “si” clause with present verb

Question

I came across a site which lists the types of "si" clauses. The one I'm confused with is "si" + present verb. It says the resulting clause will either be in the present, future, or imperative. My question is: can the resulting clause either be present/future? As in, can the two tenses be used interchangeably without changing the meaning of the sentence?

For example:

Si j'ai le temps, je jouerai au frisbee le weekend.

vs.

Si j'ai le temps, je joue au frisbee le weekend.

Do the two sentences have the same meaning? Is one of them grammatically incorrect?

Answer 1

Both sentences are correct.

There is a slight difference in meaning. In the first one, the person will play freesbee during future weekends while the second one is about a custom that include past weekends too.

In the second sentence, si can be replaced by quand, lorsque, or chaque fois que without significantly changing the meaning while in the first one, only si is acceptable.

Answer 2

As Jiliagre says, both sentence are grammatical with distinct meaning. In the second sentence, quand would be more common than si if it's meant as a regular thing you do every weekend. If it's meant to cover only the coming weekend, the formulation would be in the future with ce weekend or le weekend prochain.