It happens every year. Players who have done next to nothing for much of the season come alive and put up huge numbers in the NFL season's stretch run. Fantasy football owners who are quick to realize the potential of such players can take advantage and ride them to playoff success.

Here is a look at four guys, one at each of the four major fantasy positions, who haven’t done a whole lot to date, but who are poised to explode, meaning that they should be immediate trade targets for you. Pull the trigger on this quartet now, because once they put up a few good games, it will be too late.

QUARTERBACK: JOSH FREEMAN, TAMPA BAY
Now I'm not saying you should be starting Freeman over Drew Brees or Peyton Manning. But I am saying that if you have a starter at quarterback who's not a sure thing, Freeman can be a valuable asset.

He only had one game without a touchdown pass in the first half of the season. There are a few tricky spots on the schedule, but nothing too daunting. And the best news concerning Freeman's fantasy prospects down the stretch is that he's got home games in balmy Tampa in Weeks 15 and 16, which is prime fantasy playoff time, against Detroit and Seattle. Grab him now, and he just might pay off for you at the most crucial point of the season.

RUNNING BACK: SHONN GREENE, NEW YORK

Greene went extremely high in most drafts after his playoff success last year, but some early season fumble-itis and LaDainian Tomlinson’s surprising resurgence put him on the back burner. Check out LT’s last three games though: Less than 60 yards and less than four yards a pop in each. It could be that the veteran is wearing down, and he hasn’t got through a year injury-free in ages.

Greene’s owners are probably stewing about the fact that he’s scored just once this year, so you might be able to get a potentially huge second-half producer for a song.

WIDE RECEIVER: STEVE BREASTON, ARIZONA

Breaston has only been on the field for only five games this year because of injury, but in two of those five he recorded over 130 receiving yards. Now healthy again, he’s set for a big boost because the Cardinals schedule gets ridiculously easy from this point on.

Five out of Arizona's next seven games are at home, and there’s not an imposing pass defense anywhere on the horizon for them to face. I’m guessing that Derek Anderson holds onto the job from here, which should also help Breaston’s cause. He’s never been a big TD guy, but I think he’ll rack up close to 600 yards in the second half of the season, which makes him a dangerous fantasy entity.

TIGHT END: HEATH MILLER, PITTSBURGH

I’m going here just based on track record alone. Miller has averaged better than five touchdowns per year up to this point in his career, so the fact that he’s grabbed one thus far in 2010 makes me believe that he’s due for an upswing. His numbers have been slightly up since Ben Roethlisberger came back, and I think that he can provide starter-quality numbers from this point out.

What’s even better is that you might not even have to trade for Miller. He’s been so quiet that he just might be available on the waiver wire in your league. Scoop him up now if you don’t have one of the prime guys at tight end, and you just might get some surprising production out of him down the stretch.