If they are easing the burden on each other, then it would make sense that they will play fewer minutes
Ugh. I had a long post and my laptop ran out of juice... at any rate, I addressed this in that very same post you responded to, as well as the following post.
I'll take this a step further:
29 forwards played 20 minutes or more(excluding Byfuglien). 17 of them are listed as centers. Another 11 centers played 19 minutes or more. Let's look at some of the 20-minute centers. Datsyuk, Crosby, Malkin, Getzlaf, Kopitar, Toews, Giroux, Sedin, Tavares, Stamkos. Do you see a pattern here? If you were to make a list of the best centers in the game, the majority of these guys make it. 20 minutes per game is the
norm for an elite center. On that very same list, there are 9 Stanley Cups, and there are 14 Stanley Cup appearances. I've actually made this point previously to you, but you either ignored it, or didn't see it.
Over the course of an 82 game season, we'll probably still see Kesler and Getzlaf averaging more than 20 minutes per game, because Boudreau is going to want to get them out there as much as he can. Yes, when the score allows it, you can bet he's going to rest them when he can, because that's what every coach does, but he isn't going to sit Getzlaf on the bench for 3 extra minutes per game(which is what you're suggesting) just because he has Kesler there. Or vice versa.
Do you remember in 2005-2006 when we had Scott Niedermayer? That dude was Mr. Everything for us that season. He played 25+ minutes per game that season. That off-season, we added Chris Pronger. Did Niedermayer's numbers drop? No. In fact, they went
up. He went from 25+ minutes per game to 27+ minutes per game. What Carlyle was able to do, with that 1-2 punch, was he was able to spread out some of the tougher minutes, actually giving Niedermayer more ice time by shuffling the responsibilities a bit, and likely making sure that some of the minutes were a little easier, even if the bulk of them were hard minutes.
Now, I'm not saying that Boudreau will increase Getzlaf and Kesler's minutes(I actually expect a very slight decrease, to just over 20 minutes per game), but the point is that having that 1-2 combination will allow Boudreau to siphon off some of the harder minutes onto Kesler, giving Getzlaf the opportunity to play a lot of minutes, but in different situations; likely more favorable ones for an offensive talent like Getzlaf. He's still going to want to get them out there as much as he can, because players like Kesler and Getzlaf are the ones that win you hockey games.