This phase II trial studies how well bevacizumab, fluorouracil, leucovorin calcium, and oxaliplatin before surgery works in treating patients with stage II-III rectal cancer. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Drugs used in chemotherapy, such as fluorouracil, leucovorin calcium, and oxaliplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving bevacizumab together with fluorouracil, leucovorin calcium, and oxaliplatin may be an effective treatment for rectal cancer.