Kittle (calf) is listed as doubtful for Sunday's game against the Cardinals, Nick Wagoner of ESPN.com reports.
Kittle reportedly wasn't able to do much at Friday's practice, attempting a return after missing Wednesday and Thursday. He played through the same calf injury and handled a full workload last week, though he caught just four of 11 targets in the 49ers' loss to Seattle. It now appears Trey Lance will make his first NFL start without the help of his team's best offensive player, with TE snaps instead going to Ross Dwelley and Charlie Woerner. The team then has a Week 6 bye, followed by a Sunday night home game against the Colts in Week 7 (Oct. 24).