Campoli was injured to start the season, was dropped to the minors for conditioning purposes and then struggled to get back into the line-up because the rest of the defense was playing so well. He spent an extended period in the AHL, playing NHL now after Zhitnik deal and injury to Meyer. Last year he was the top defender on the team in terms of points (though Zhitnik missed 23 games compared to Campoli's 2 and was only 5 points shy). Nonetheless, still a very good preformance in his rookie year. With Meyer back, he may lose his place in the team again - ask an Islander fan. If he gets the minutes he got last year and finds the same form, he will produce like he did last year, especially since the team as a whole has made vast strides over last year's team.
Brent Burns has been playing mostly 4th line RW in Minnesota. Even when Foster was injured and a slot opened up in the 6 dman slots, the Wild recalled Shawn Belle to the team for 4 games before they put Burns back there. Now Foster has returned, I believe he is back to RW. May be some time until he starts producing like a top 4 dman, probably not until next season.
Mike Green played the majority of last year in Hershey, coming up to the NHL towards the end of the season. Now is averaging just over 17 minutes per game. Don't know much about his situation, been healthy all year, played in the NHL all season. Not playing badly, but not playing brilliantly.
Barker began the year injured and has been in Norfolk since he recovered. I read comments from Blackhawks fans expecting him to be recalled to the team soon after Christmas, though this was several weeks ago now. With 7 defensemen on the roster in Chicago right now, he may be forced to wait a while longer. An injury to one or two of these guys might give him an opportunity. If he plays well he'll probably stick, similar to James Wisniewski earlier this year; if he doesn't quite meet the mark, he'll most likely be sent down again, similar to Danny Richmond. With the recent addition of Bruno St. Jaques from Anaheim, Danny Richmond and Dustin Byfuglien playing well so far this season (coupled with good play last year in Chicago after being called up), there will be stiff competition for a call up if injuries continue to hit the Blackhawks this season. May take a similar pattern to Mike Green last year, called up for the last 30 games or so. Will cement himself over next season as a top defenseman of the future.