Suppose Bernard Pollard had missed Tom Brady’s left knee on that sunny September day five years ago. Suppose those Hall of Fame-bound ligaments hadn’t been snapped leaving the league’s flagship franchise in the hands of a 26-year-old kid who never had even started a game in college let alone the NFL.

“I guess we’ll never know” said Matt Cassel that former kid and current Vikings backup quarterback. “But all I know is I was in my fourth year and he was Tom Brady quarterback of the New England Patriots. No one else was going to step on that field unless it was a mop-up deal. But it turned out …”

Cassel paused. He has reached that moment in the conversation. The moment that’s honest and innocent yet still uncomfortable to say out loud for a backup at the one position in which starters play until they are seriously injured woefully inept or insurmountably ahead.

“Unfortunately for Tom and fortunately for me” Cassel said “things turned out well for me.”

Had Pollard missed that knee? Well let us count three possibilities:

• Brady probably would have finished that opening-day victory over the Kansas City Chiefs and completed the season. Why? Because that’s what he has done every other year since 2001.

• Josh McDaniels might have remained a young Patriots assistant coach hidden in Brady’s considerable shadow instead of becoming head coach of the Denver Broncos.

• And Jay Cutler might still be the quarterback in Denver. Why? Because McDaniels wouldn’t have been forced to trade Cutler to Chicago after a failed effort to acquire Cassel a nobody who never would have become a high-priced somebody had he not gone 10-5 in Brady’s absence.

“I’ve been very blessed” Cassel said. “The part about me not starting [at Southern California] is probably the craziest part in all of this. To go from that to actually getting drafted [in the seventh round in 2005] and going to the best situation possible with the Patriots is being blessed. Being mentored by Tom Brady and then getting an opportunity and then being ready for that opportunity it’s proof that you really are one play away from everything changing.”

For the first time since 2008 Cassel enters a season as the designated No. 2 quarterback. But this time is different. This time he wasn’t drafted to fit a particular system. This time he picked the interested party that best suited him. This time he’s backing up Christian Ponder a third-year pro who has reached a career crossroad. Feel free to read between the lines.

Cassel will make $3.7 million — including a $2 million roster bonus and a base salary of $1.65 million — this season. That’s a nice sum for a veteran backup but not so hefty that it undermines the Vikings’ steadfast argument that Ponder is their starter this season. Yes Ponder will make less money ($1.3 million) but that’s the result of operating under a rookie contract not the team’s judgment of his value compared with Cassel’s.

Where things could get interesting is the second year of Cassel’s contract when either side can opt out of the deal without further salary cap ramifications. In other words if Ponder’s career solidifies Cassel can choose to leave rather than stay on as a backup. If Ponder’s career disintegrates the Vikings could change starters relatively cheaply. Cassel would be paid $4 million and Ponder would receive his guaranteed $1.76 million salary for 2014.