Complex sentence: Centre Ryan Kesler, who was recovering from off-season surgeries to his shoulder and wrist, would be unable to start the season; it was unknown how long he would be out rehabbing the injuries.
Split into simpler sentences: Centre Ryan Kesler, who was recovering from off-season surgeries to his shoulder and wrist, would be unable to start the season. It was unknown how long he would be out rehabbing the injuries.