The Giants remain mum on who will start Tuesday’s game in place of injured right-hander Ryan Vogelsong, but manager Bruce Bochy expects a decision Sunday.

“We probably have to get it nailed down by tomorrow,” Bochy said before Saturday’s matinee against the Colorado Rockies.

Bochy added that he’s talked to reliever Chad Gaudin just to brief him on the situation, but he didn’t reveal whether he told Gaudin to prepare himself for a potential start. The right-hander has 75 major league starts on his resume, but the Giants value his versatility in the bullpen.

He can be used in short or long relief, and that might dissuade team officials from wanting to plug him into the rotation to replace Vogelsong, who will miss several weeks with a fractured throwing hand.

Factor in that the Giants are already without right-handed reliever Santiago Casilla, who might undergo surgery on his right knee, and they may be even more inclined not to move Gaudin into a starting role.