Once a player calls a time-out, this is a stoppage. So no turnover is possible.
If the team had no time-outs left, then 20.5 applies:
The marker must add two (2) seconds to the stall count they would have restarted play on before restarting play with a check. If this results in a stall count of ten (10) or above, this is a “stall-out” turnover.