Some information for you all to know...
While there are no laws that dictate a specific time frame to wait after a layoff before filling a position; there are several reasons an employer should proceed cautiously when hiring for a position that was recently part of a reduction in force or job elimination. Handled improperly, an employer may be accused of using the position elimination as a pretext for what would otherwise be an unlawful termination. A former employee may attempt to sue an employer for wrongful discharge within state and federal statute of limitations time frames.
As with all negative employment actions, the reasons should be lawful and justifiable. If there truly is no longer a need for a position, and the employer can show business need for the elimination, it would generally be permissible to terminate employment for position elimination. It would be reasonable for an outsider to then believe this to be a permanent elimination, and not expect the employer to rehire for the position within a short time frame.
However, if the employer does try to rehire for the position within six months or less for example, and the former employee finds out the new hire or replacement is younger than him or herself (age 40 or under), of a different race, religion, gender, less qualified, etc. it may cast doubt on the legitimacy of the position elimination in the first place. If the employer then cannot show the business need for the elimination, it may find itself in legal trouble. In short, position eliminations should not be used as a quick fix for easily eliminating a poorly performing employee.
If, after a position elimination, the employer discovers that the position really was needed, it should be able to demonstrate why the person eliminated wasn't offered to be reinstated or clearly demonstrate how the role changed and why the person eliminated cannot fulfill that new role.