I think they had mentioned that they were going to keep wearing the black jersey's as long as they keep winning with them.
As for the Panthers, despite the injuries they have been playing fairly well. J.Bo is starting to show signs of life and putting up some good numbers lately. We should win this one, but it should be a close game and the Sens will need to keep up the effort for the full 60 min.
Probably sells more jerseys this way. If one team really likes the alternative, more so than they regular home jerseys, this prevents them from phasing them our and replacing him. More revenue from jersey sales, and doesn't create any contract issues with Reebok (that's who makes the jerseys right?) if one jersey is no longer used.
Not saying that's the exact reasoning, but that's what makes sense in my head.