How big of a piece? I have had BPs eat a tiny bit of substrate and are fine years later. But if your talking Big Bark or something then that may be a cause of concern. Approximate how big?
Nothing to worry about. Balls can easily digest the occasional wood chip without a problem. You may want to watch that it doesn't get caught in its mouth as that can lead to some problems, but that's about it.
The substrate that you heard was bad was probably either pine or sand/gravel. Sand/gravel can cause compaction problems in Balls amongst other problems, and pine is toxic.