Some Probationary Employees May Have Employee Rights
Some probationary employees, if they meet certain criteria, have the same or similar rights as non-probationary federal employees. So, while the label “probationary” makes it seem like these employees have little to no rights, that might not actually be the case for some.
According to the link below,
An employee is defined in 5 U.S.C. 7511(a) as follows: "Employee" means— (A) an individual in the competitive service— (i) who is not serving a probationary or trial period under an initial appointment; or (ii) who has completed 1 year of current continuous service under other than a temporary appointment limited to 1 year or less; (B) a preference eligible in the excepted service who has completed 1 year of current continuous service in the same or similar positions— (i) in an Executive agency; or (ii) in the United States Postal Service or Postal Rate Commission; and (C) an individual in the excepted service (other than a preference eligible) - (i) who is not serving a probationary or trial period under an initial appointment pending conversion to the competitive service; or (ii) who has completed 2 years of current continuous service in the same or similar positions in an Executive agency under other than a temporary appointment limited to 2 years or less.
More info can be found here: