49ers backup QB competition too close to call after preseason loss

NASHVILLE, Tenn. — Brock Purdy took a backseat to the backup quarterbacks in the 49ers' preseason opener Saturday night against the Tennessee Titans. And through two weeks of practices and one preseason game, the competition for the No. 2 job between Brandon Allen and Josh Dobbs still appears too close to call. "I thought they did a good job," 49ers coach Kyle Shanahan said. Allen led the 49ers to a first-drive touchdown. Later, he converted a third-and-9 from his own end zone with a nice toss to receiver Frank Darby down the middle of the field. Allen completed 7 of 13 passes for 98 yards, and missed two potential big plays when receivers Tay Martin and Ronnie Bell failed to haul in deep contested throws. "I have been in similar systems where we have similar reads and plays," Allen said. "I have always been comfortable throwing over the middle. I don't know why, but I do feel like I can see the field well. I'm really comfortable with having things develop over the middle of the field and being able to see it." Allen played all 25 snaps in the first half. Dobbs took over in the second half and was on the field for the 49ers' final 31 offensive plays. Dobbs completed 14 of 20...