I am needing to know if a baseball player can sign a major league contract for any time frame including less than a year? Is there any rule, policy, etc. against his doing so?

They can sign 10 or even 30 day contracts... Lance Parrish in the 90's signed a contract with the Toronto Blue Jays.

I am needing to know if a baseball player can sign a major league contract for any time frame including less than a year? Is there any rule, policy, etc. against his doing so?
MLB Contracts can be as short as one day