The Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary lens for Nikon F mount is scheduled to start the shipment at the end of this month according to Sigma Japan.
Adorama and B&H are currently taking pre-orders.
Additional information on this lens can be found here. The Contemporary model is lighter, cheaper ($1,089.00) and with a slightly simplified lens design compared to the Sport model that is almost twice as expensive: