Todd Frazier never had to ask Paul O’Neill if it was OK to wear No. 21 because it wasn’t up to O’Neill.

Frazier talked to clubhouse manager Rob Cucuzza about trading No. 29 for O’Neill’s Yankees number, but was told that wasn’t going to happen.

“I talked to some guys and 29 it is,’’ Frazier said before starting at third base in Thursday’s 4-1 victory in Seattle and going 1-for-4 with a run scored. “It’s a great number [21], but it doesn’t bother me.’’

Frazier was assigned No. 21 when he broke into the big leagues with the Reds and that was the number O’Neill also wore for the Reds.