Libero injury, redesignation, and roster change
 

NFHS, Ohio. Libero (#15) is injured during warmups and enters & attempts to play in the first set but cannot continue. #15 is the only libero listed on the roster and the team only has one contrasting jersey (the one she is wearing).

Can #25 on the roster change into jersey #15 and play as the libero without a point/loss of rally penalty?

Yes. See case 10.4.3C