Yes, he'll get a chance sooner or later be it through form, injury or suspension. Onuoha has made a serious rick in each game but has otherwise been good. I'd rather persist with him for now especially when the team is playing well overall than bring in a player who probably isn't fit and has been at the club a week or a player we're trying to sell (presumably) who is totally unreliable in just about every sense of the word.
I'd expect to see Baptiste in the cup.