My guesses are based on two considerations: the season is broken up into two/three sections for the purposes of integrating Lehtonen, and that he's able to transition the way some of those who've analyzed him suggest he might fit because they are correct in their opinions of his skill sets. To the second consideration first: Lehtonen is cautious, intelligent, has some jam, good gap control, decent skating, can avoid the first checker in the Dzone, has a good first pass, doesn't try to do more than he can, positions himself well between the goal and the attacking player, has a good shot on net that get's through...in short a solid player. If these views are correct, he is an improvement on Ron Hainsey, and if paired with Rielly would provide useful skills that compliment Rielly (such as: steady defensively, able to pass to Rielly, able to avoid initial press and move the puck to advancing forwards, a threat from the point). To the first consideration, he will need time to acclimate to the NHL. That he is a mature player should help speed up the process...will it be successful? I hope it is.
Segment 1: 1st 20/30 games
Muzzin Holl (more defensive zone starts)
Rielly Lehtonen (more offensive zone starts)
Sandin Dermott (dependent on game situation leaning towards O zone starts)
Rosen/Liljegren
If things prove successful...
Segment 2: Games 25/50 ish
same pairings with the intent of a more balanced work load re: zones. To determine the strengths and weaknesses of all of our D pairings. I want all our pairings to have gained confidence in their understanding of how they fit with the team and their importance to the team. I don't want one of the pairings to feel as if they are the 'weak' link...they will all be needed come playoffs. This is where fine tuning comes into play. Dermott might flourish and Lehtonen flounder, Liljegren may blossom, injuries of course, and if we see a compressed schedule, I'd be introducing Rosen and Liljegren into selected games to reduce wear and tear. Essentially, establishing the foundation for our push.
Segment 3: the last 30 games.
The strength of this team is in its offensive capabilities. I want to see Rielly on the ice more than any other Dman. Thus...
Rielly Lehtonen (around 23/4 minutes)
Muzz Holl (around 20/21)
Sandin Dermott (15/6)
Realistic? Eh, who knows, I'm sure there are more than a few here who will tell me I'm crazy. I just might be