49ers mail call:

Jason from San Francisco wants to know if I think Blaine Gabbert is definitely going to be the 49ers' backup quarterback this season.

Bill Williamson: It appears certain that Gabbert will be Colin Kaepernick's backup. His contract of $2.1 million is guaranteed. The 49ers knew this when they traded for the former No. 10 pick,and they didn't add a quarterback in the draft although they did just sign Josh Johnson, who has a history with Jim Harbaugh. Still, Gabbert is the favorite to be the backup. As for the future, it depends on how the 49ers' staff feels about him. But he is clearly a player the coaches want to work with.

Harry from Dallas wants to know if I think third-round pick Brandon Thomas has a chance to play this season.

BW: I doubt it very much; the 49ers are looking for the Clemson product to perhaps play in 2015. He tore his ACL during draft preparations. The chances of Thomas being ready any time this season are slim, but this was a pick for the future, anyway.

Marcel from San Jose wants to know what I expect from fourth-round cornerback Dontae Jonson as a rookie.

BW: I think the 49ers want to see him become a special teamer and show he can play in dime situations as the season progresses. Johnson has the size, athleticism and intelligence to become a good player. The team is really high on him, especially for the future.