SANTA CLARA – When Colin Kaepernick brought a jolt of energy to the 49ers' offense Sunday in the Meadowlands, you could almost feel the anti-Alex Smith crowd stampeding to their keyboards.

"HOW LONG," they typed, exclamation points flying, all-caps locked in, "UNTIL KAEPERNICK REPLACES SMITH AS THE 49ERS' STARTING QUARTERBACK?"

You might have thought the 49ers were losing 34-0.

They weren't, of course.

Smith is 17-5 as the starting quarterback since Jim Harbaugh became coach before last season, and his 77 percent victory rate is third best in the league over the same span behind the Packers' Aaron Rodgers (80 percent) and the Texans' Matt Schaub (78 percent).

Smith's above-all-do-no-harm style might exasperate some fans, but it fits in nicely on a team with a strong defense and an excellent place kicker.

What's more, the 49ers now have the perfect half-dozen-plays-a-game complement to Smith in Kaepernick. The team's offense is built on sending wave after wave of different personnel groups at the defense, and Kaepernick – so dangerous as a runner – is yet one more weapon that opponents have to study and face in a game.

The 49ers drafted Kaepernick early in the second round last year, and the expectation is that he'll eventually take over the starting job.

When that happens, however, is fuzzy, but April 1 is a key date.

If Smith is on the 49ers' roster on that date, his $7.5 million base salary for 2013 becomes guaranteed. If the 49ers release Smith on or before March 31, they will save $7.5 million.

That's not an insignificant amount.

It's possible the 49ers will conclude that Kaepernick is ready to take over and they should cut ties with Smith, especially if Kaepernick continues to spark the team like he did Sunday.

Perhaps they'll decide their monetary priorities should be on defense and that they need that $7.5 million to help sign starters Justin Smith, NaVorro Bowman or Tarell Brown, all scheduled to become free agents after the 2013 season.

But when compared to salary-cap space other teams carve out for their quarterbacks, the amount earmarked for Smith in 2013 is picayune.

This year, Smith will make $8 million, which ranks 20th in quarterback salaries and places him between Kansas City's Matt Cassel ($9.7 million) and Tennessee's Matt Hasselbeck ($6.7 million).

All the other quarterbacks below Smith either are non-starters or are starters who are still on their rookie contracts.

Next year, Smith is due to earn $8.5 million overall. Even when you add Kaepernick's 2013 salary – $850,000 – to the mix, the 49ers will rank in the lower third of the league in quarterback spending. They can hold onto both and still spend less – in most cases, far less – than two-thirds of the league.

And therein lies the double-edged sword for the vocal group of fans who have been counting down the days to Smith's departure.

The modest amount the 49ers are paying Smith – relative to other quarterback starters, of course – shows that they aren't all-in for Smith, despite Harbaugh's relentless praise. But it doesn't force the issue, either.

In fact, the true impetus doesn't come until after the 2014 season, when both Smith's and Kaepernick's contracts run out.

For now, the 49ers can take their time with the decision. They can afford to ride into 2013 – and perhaps beyond – with both quarterbacks.

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