It depends how bad the injury is. I remember Ertz playing with it. if it's a minor it should heel quick. worse it's 4-6 weeks. The most severe needs surgery.
A direct blow to the back is the most common cause of a kidney laceration. Lacerated kidney symptoms and signs include blood in the urine, nausea, vomiting, and abdominal, flank, and back pain. Read about treatment and recovery time.