I'm not sure how much those trades will affect Murphy's deployment, as it looks like he spent most of his time as the RHD #3 behind Gustafsson and Seabrook. Maatta and de Haan are both LHD, so they'll likely slide in behind Duncan Keith to round out the left side.
Where things get a bit complicated is with Henri Jokiharju and Adam Boqvist, both RHD, pushing for roster spots. If you expect Jokiharju to make the opening night roster and play most of the season with Chicago, then Murphy is probably the odd man out on the right side. It's pretty safe to assume that Boqvist won't be making the roster just yet, but Jokiharju is a big question mark. Certainly, he showed last year he's capable of handling himself well in the NHL, but the organization may feel it's better for his development to continue to dominate in the AHL for another full season before breaking into the big club's top-four on a permanent basis.
It's clear to me that Gustafsson is cemented as their top offensive / PP1 guy, so there's no need to rush a youngster to fill that role. 17 goals and 60 points last year was an impressive feat, especially compared with the short stint Jokiharju had on the top PP unit that he was largely unable to translate into production (although there were flashes of brilliance). If I had to guess, I would say that Jokiharju spends most of this season in the AHL on a safer development path. This would mean that Murphy should be pretty secure in getting those third-pair minutes with some upside for more because Seabrook is only getting worse.
They'll go with some combination of: Keith/Gustafsson, de Haan/Seabrook, Maatta/Murphy -- I'd expect Jokiharju will see some time with the big club, and this will probably come at Murphy's expense.