Alex Smith, before Jim Harbaugh’s arrival: Five seasons, 51 TDs, 53 INTs, never a completion rate above 60 percent, highest yards per attempt 6.9., and a hideous record of 19-31.

In 18 regular season games since Harbaugh took over:

21 TDs, 4 INTs
completion rate: 62.3
Yards per attempt: 7.1
record: 15-3 record

Before Harbaugh’s arrival: ALEX SMITH IS A BUST! Remember how, after Harbaugh passed on the Dolphins and picked the 49ers, the coach surprised many by saying the 49ers would sign Smith to a 1-year deal? And then San Francisco drafted Nevada QB Colin Kaepernick in the 2nd round? It appeared as if Smith wasn’t the long term solution.

But as the NBC crew noted Sunday night against Detroit: Smith, the No. 1 pick in 2005, is all grown up. Smith was brilliant against Green Bay in the opener, then superb again against the Lions.

This was a masterful recognition of Detroit’s defense, changing the play – Davis was going to have double coverage up top, so he sent a player in motion – and then throwing the TD pass.

Is it Jim Harbaugh’s simplified playbook? Has the improved defense had that much of an impact on his confidence? It isn’t like his offensive weapons are different – Frank Gore and Davis were there for the lean Alex Smith years.