Probationary often means you are being evaluated to see if you're a good fit for the job or group. As a probationary member of the team, his performance was closely monitored.
Pro Tip 2/3
Temporary Status
The term emphasizes a temporary phase which can lead to permanent status if successful. If she performs well during the probationary phase, she'll become a permanent employee.
Pro Tip 3/3
Limited Privileges
A probationary period may come with fewer benefits and rights than those of regular status. Probationary workers may not have access to the same health benefits as other employees.