San Francisco 49ers head coach Kyle Shanahan said wide receiver Jauan Jennings is on course to play in the team’s Week 1 road opener against the Seattle Seahawks. Jennings has been nursing a calf injury, but Shanahan indicated the 26-year-old should be medically cleared in time for the September matchup. Shanahan confirmed that fellow receiver Jacob Cowing suffered a fully torn hamstring that will keep the rookie out for at least six weeks. The timeline makes Cowing a strong candidate for one of the club’s two injured-reserve slots that permit an in-season return, with defensive tackle Kevin Givens viewed as the other likely designee. The contrasting updates leave San Francisco projecting better depth at receiver for the opener while planning to adjust its 53-man roster before the August 27 deadline. Cowing’s absence could open opportunities for other young pass-catchers as the 49ers finalize preparations for the trip to Seattle.