Renney has never been shy about moving defensemen in and out of the lineup. If Staal is hurting you can bet that Potter will get to play early on this season. And if the Mara/Kalinin pairing have a bad game (i.e. -3) you can bet you'll see the #7 dman get a chance. With the top four being set I would expect that third pairing will be tinkered with all year. Staal/Rozsival, Redden/Girardi will play about 50 min a night so the third pairing is mostly going to play on the PK and early in games.
All things being equal--meaning if everyone on the blueline is healthy--neither are on the NHL roster to start the season. They're both fighting to prove they are NHL caliber defensemen, who can be trusted to play in the event of injury or other problems.
I don't think I'd have a problem with either of them making the team--though I do think Potter's been a little better. As for whether he'll get enough playing time--to me NHL experience is always a good thing. We can send him down now and again if we need to--to get him back in game shape. Potter is 24 in any case--he's not that raw--he's already been through much development and I don't think we're going to be curtailing much of his upside. It should be kept in mind that if someone gets injured and Fahey is 7th and Potter is on the Pack--Renney is going to give Fahey the shot first--deserving or not.
the one thing i have noticed with potter that really impresses me is his lateral movement on the blue-line.....he does it with such ease and with such calm that its nice to see a young defenseman who can move laterally on the blue-line to get around a forward trying to block a shot.....honestly, i havent seen that since leetch on the rangers blue-line.......(not trying to compare him to leetch).....he has done it a few times and every time it's impressive