My LHP son has several offers of various remuneration but is only now taking his second and third official visits which will take him up to the end of the early signing period. What happens if he decides to not sign during this period? Can he still verbally commit anytime after that? Will D-1s and mid-majors still have slots open after November 18th?

If you are talking D1, and doesn't sign during the early signing period, he needs to wait until April to sign again, but can still commit anytime.

Signing means the recruiting process ends, if one doesn't sign in November he still can entertain all options.

I assume by your question that the "ideal" school isn't offering?

In D1, you will find very few schools that hold on to scholarships after early signing period. They will often just move on to their next choice.
There are exceptions,for sure!

Some schools will lose scholarship kids at semester break,due to many factors, including being cut or told that they won't play the next year. That would then free up $$ for the Spring period.

The draft could be a factor, but often it isn't until August until they know if a drafted kid will sign with a MLB team.

A lot of kids will sign early with a viable JUCO program, which still allows them to be 'free agents', so to speak, for D1 or D2 schools in the Spring. And, if those don't come, he still has the opportunity after his Freshman or Soph year to move on to a 4 year school.

It's a "roll of the dice" to wait, but sometimes it can be worth it!

Best of Luck!

If I were the coach that made the offer and it was a fair one, your son would be off my list and I would move on to my next choice. The large programs have plenty of good players wanting to play for them.

Maybe some of our coaches can give their perspective.