Breida suffered a slightly torn pectoral muscle while lifting weights but is expected to be ready for the start of training camp, Matt Maiocco of NBC Sports Bay Area reports.
The injury isn't believed to be too serious, but Breida still will be held out of all workouts until the start of training camp, when he is expected to be cleared. Breida should have a significant role in the 49ers backfield this season alongside Tevin Coleman and Jerick McKinnon (knee).