The fantasy regular season is approaching its end. This is Bernie Federko Jersey when it gets real. But it's also the time to start building your roster for the postseason. As we move closer to the fantasy postseason, Reading the Defense will start taking a look at some of the guys who could go boom or bust in the playoffs. Let's get to it.Trending up, DL, : Campbell is putting together a season, something that would have been hard to imagine considering the lo ses Arizona has suffered on defense this season. Nonethele s, Arizona's playmaking lineman has racked up five sacks in the past three games and faces a fairly tantalizing matchup down the stretch. With the still chasing the division title, they'll need Campbell to continue to play well.Playoff schedule: vs KC, at STL, vs SEA, LB, : Moore gained unwanted attention for his in the win over Kansas City. But that shouldn't overshadow the play of a man who has quietly put together a nice season for the Silver and Black. He'll end it with three matchups that look a lot more favorable now than they did at the start of the season.Playoff schedule: vs SF, at KC, vs BUF, DB, : It's probably gone unnoticed in many quarters, but McDonald is having quite the IDP season. Like many of his teammates, McDonald has improved as the season has progre sed. Things should only get better as St. Louis lines up against a trio of teams with definite deficiencies in their pa sing games to end the season.Playoff schedule: at WAS, vs ARI, vs NYGTrending down, DL, : Young had a quick start to the season, racking up seven sacks in Chicago's first five games. Since then, things have slowed considerably. Young has notched just one sack since Week 7 and will face some frustrating offensive line matchups through the fantasy postseason. Time to get bearish on this Bear.Playoff schedule: vs DAL, vs NO, vs DET, LB, : Worrilow had a break out season in 2013 and has followed it up with an even stronger campaign in 2014 -- all while playing in the midst of one of the NFL's worst defenses. However Worrilow will need to be Superman to singlehandedly chase down some of the offensive weapons he and the will face over the final few weeks.Playoff schedule: at GB, vs PIT, at NO, DB, : The secondary has not been as formidable as in seasons past, which could eventually take its toll on Jones' production. In addition, Cincinnati faces a trio of teams that have been fairly efficient in the pa sing game, including a team that has back in action.Playoff schedule: vs PIT, at CLE, vs DENFour downs The got back in their lineup, but now it appears that they will have to go without their best playmaker on defense. , who leads the NFL with six interceptions, suffered an and is expected to mi s the remainder of the regular season. Gipson's absence is likely to thrust into a larger role. Poyer, in his second NFL season, has yet to start a game in his career and has recorded only nine tackles this year. It seems that we were premature in proclaiming big things for in 2014. The No. 1 overall pick has been limited by injuries all season long and says he's still not at . We've seen Clowney pick things up in the couple of games since his return but it looks like we're going to have to wait until next season to see him get closer to his potential. At least there's always . linebacker left Sunday night's lo s to the with a knee injury and was set to on Monday. The good news is that the injury doesn't appear to be serious and McClain could suit up and play in Big Blue's Week 13 contest at Jacksonville. That's good news for a player who has been able to rack up tackles at the middle linebacker position after the lo s of to injury. The could have linebacker back in action as soon as as he recovers from a cracked bone in his knee. The move could leave questions as to what happens with . The third-year linebacker has played very well and currently sits as the fourth-best IDP linebacker. It's hard to think Trevathan's return will completely push Marshall out of the lineup.Marcas Grant is a fantasy editor for NFL.com. Follow him on Twitter . Josh Jacobs Jersey