Vikings training camp snapshot: Quarterbacks

Aaaaand …. here we go! In many ways, the Vikings' 2013 season officially gets underway Friday – first training camp walkthrough at 10:30 a.m., first practice at 2:30 in Mankato. And yes we know a lot can and will happen between now and Sept. 8, the day the Vikings open the regular season at Detroit. But taking the 90 players currently on the roster, we're delivering our in-depth position-by-position report as a primer for the opening of camp.

QUARTERBACKS

Currently on roster: 4

Likely to make opening day roster: 3

Certain to make the team: Christian Ponder, Matt Cassel

On the bubble: McLeod Bethel-Thompson

Camp depth: James Vandenberg

What we'll be watching: We'll have our eyes on Ponder, checking to see if his decision making can be more reliable, his deep throws more accurate and his leadership galvanizing. But be forewarned, we're not going to cast a verdict on Ponder's future at any time during training camp. No matter how sharp he looks on certain days, no matter how badly he struggles at times, we won't know for certain just how much progress the third-year quarterback has made until the regular season starts. Truth be told, Ponder probably deserves all of September to put his development to the test. So check back with us when we return from London – if we return, that is – with any questions as to whether Ponder still deserves the coaching staff's unwavering support as the starter.

Star Tribune offseason excerpt:

Cassel, a starting quarterback for the past five years, said he accepted the role as Christian Ponder's backup, calling the Vikings 'a perfect fit' when he spoke with the media a day after his signing.

"I understand the role completely," Cassel said. "Without a doubt."

The Vikings weren't going to sign anyone who couldn't convince them of that. Since selecting Ponder 12th overall in the 2011 draft, General Manager Rick Spielman and coach Leslie Frazier have been extremely careful not to waver in their support of Ponder, who has struggled at times while posting a 12-14 record and a completion percentage below 60 percent (59.2).