The next logical step, however, is to wonder why that wasn't done earlier, say, as soon as it became obvious Culpepper wasn't moving well.
The opener at Pittsburgh provided a clue, but there could be no doubt after the Week 2 loss at home against Buffalo when any kind of quarterbacking would have been enough to get the Dolphins a victory.
That day, Culpepper's lack of movement and indecisiveness in the pocket were terribly apparent to anyone who was watching.
Here's the second part of the equation: Harrington is the better option at quarterback for the Dolphins, but don't think all their offensive problems are going to disappear because he's in the game.
We saw that last week at New England when Harrington actually played pretty well, yet the Dolphins managed only 10 points.
The offensive line has been and continues to be the biggest problem on offense, and there's no guarantee it's going to get significantly better anytime soon.
But at least Harrington right now gives the Dolphins a fighting chance. He will set up in the pocket quickly and get rid of the ball quickly, and that will help the offense.
If something should happen to Harrington, we'd probably get our first look at Cleo Lemon in the regular season, but that needs to be a last resort. Yes, the guy looked great in the preseason, but that's a whole different game.
This, really, is about Harrington and Culpepper.
Harrington gets a big chance right now to show he's a better quarterback than the one who struggled for four seasons in Detroit. Our sources in Motown tell us that Harrington is a highly talented quarterback who just got dragged down by a bad supporting cast and a losing culture that obviously still persists -- based on the Lions' 0-5 start this season.
The feeling here is the Dolphins offense could be solid if the offensive line could only perform as it did late last season.
As for Culpepper, the primary focus is to get him back to 100 percent, regardless of when that happens. The Dolphins have too much invested in him to settle for anything less.
If it doesn't happen this year and Culpepper has to be shut down and put on IR, so be it. The trade with Minnesota wasn't made with only 2006 in mind; it was made to settle the quarterback position for years to come.
Besides, how many realistically expected Culpepper to be a stud right away considering he was coming back from that devastating knee injury?
All that happened is that Culpepper raised expectations to unreasonable levels with the way he exceeded all realistic timetables for his return to action.
In retrospect, it's obvious the Dolphins would have been better off had Culpepper not recovered so fast, but there would have been a lot of disappointment back in August if that had been the case.
Instead, the disappointment hit early in the season when it became clear that Culpepper, in fact, was not all the way back.
So the Dolphins are back where everyone thought they would be. It's just a shame it happened with them already in a hole this season.