Trevor van Riemsdyk knows what the news means as much as anyone. With all-everything defenseman Duncan Keith sidelined 4-6 weeks after right-knee surgery, it’s now all hands on deck. Everyone has to do a little bit more. And for a Blackhawks defensive corps that has suddenly gotten much younger and much more experienced, it’s going to take everyone contributing. “It’ll be a concerted effort, obviously, to fill those minutes,” van Riemsdyk said following Tuesday’s practice. “It’s going to take a little bit from everyone.” Indeed, no one guy is going to replace Keith, the two-time Norris and one-time Conn Smythe Trophy winner who can seemingly play endless minutes, and play them at a high level. Still, the Blackhawks have to figure out what to do for about a month, without changing their style drastically. “We don’t want to change too much in our approach,” coach Joel Quenneville said. “Guys are going to know they’re going to get more responsibility. With our team game, we’ll emphasize playing the right way. I don’t think you want to change too much in how you focus going into a game. Individually, guys are going to be assuming more and I’m sure they’re excited about it.”