Training camps are well underway, and we've gotten our first taste of preseason action by watching the fifth-stringers from the Arizona Cardinals and New Orleans Saints do battle in the Hall of Fame game. Which means that before you know it, Opening Night will have arrived and with it another exciting and maddening season of fantasy football. One of the annual rituals of the preseason for Individual Defensive Player (IDP) enthusiasts is getting our first look at teams that have undergone defensive scheme changes. These changing formations can have a huge impact on IDP values, boosting the stock of some players while killing the value of others, especially on the front seven of the teams in question. In recent seasons, the majority of scheme changes have been 4-3 teams switching to the 3-4, but this year the reverse is the case, as two of the biggest schematic shakeups on the defensive side of the ball involve AFC East teams making the change to a 4-3 front. Let's take a look at how these changes could affect the fantasy values of the players who will be making these switches, from one of the NFL's coldest cities to one of the warmest, with the league's biggest rebuilding project thrown in for good measure. Buffalo Bills We'll start our tour of defensive shakeups in frosty Buffalo, where new defensive coordinator Dave Wannstedt will be implementing a 4-3 scheme with the Bills. Not only are the Bills making a change in defensive fronts, but the team was also incredibly active in free agency in bringing players on-board to help ease the transition. The Bills made the biggest splash of free agency on defense by signing Mario Williams to a six-year, $100 million contract, the richest deal in NFL history for a defensive player. Now that Williams, who played in only five games a year ago before a torn pectoral muscle ended his season in Houston, is out of the 3-4 and back at defensive end, his fantasy value has reverted to its previously lofty status, and the seventh-year pro is once again one of the Top 5 IDPs available at his position. The Bills weren't finished there, though, as the team also lured defensive end Mark Anderson away from their division rivals in New England. The 29-year-old tallied 10 sacks in a rotational role with the Patriots last season. While Anderson's historically low tackle numbers make him more appealing in sack-heavy IDP formats, his relatively low average draft position of DL33 in IDP drafts at MyFantasyLeague.com, and the fact that he'll see few if any double teams in Buffalo, makes Anderson an interesting upside DL3 selection. The combination of Williams, Anderson and defensive tackles Marcell Dareus and Kyle Williams gives the Bills one of the NFL's more formidable defensive lines on paper, but Buffalo's switch to the 4-3 will have a big impact on the linebacker corps as well. The coveted position of middle linebacker will be manned by second-year pro Kelvin Sheppard, but Sheppard's IDP sleeper sizzle fizzled with the news that he will leave the field in passing subpackages, which limits Sheppard's fantasy upside considerably. Meanwhile, 9-year veteran Nick Barnett, who paced the Bills with 130 total tackles last season, will move from WILB to WLB in Buffalo's new defense. Barnett has some experience manning the weak side of the 4-3 from his time with the Green Bay Packers, and while he may be hard pressed to repeat his Top 10 finish in Default IDP manor Scoring from a season ago, his "new" position, an every-down role, should keep Barnett squarely in IDP LB2 territory. Miami Dolphins At the opposite end of the East Coast, the Miami Dolphins are making a similar transition, as new head coach Joe Philbin and defensive coordinator Kevin Coyle are also eschewing the 3-4 defense in lieu of the 4-3. The biggest beneficiary of this change from a fantasy football perspective is undoubtedly fourth-year pro Cameron Wake, who will return to the defensive end position that got him a look from the Dolphins to begin with after Wake terrorized quarterbacks in the Canadian Football League. Wake had already proven adept at getting after the passer in the NFL as well, racking up 28 sacks in three seasons, and a change in positional eligibility in IDP leagues elevates Wake from a marginally rosterable big-play linebacker to a borderline IDP DL1 who presently represents a very solid value in IDP drafts given his reasonable ADP. Linebackers Karlos Dansby and Kevin Burnett finished within three tackles and two-and-a-half fantasy points of one another playing side-by-side on the inside of Miami's 3-4 a season ago. However, that gap will likely widen this year in Dansby's favor, as not only does the ninth-year pro have a more proven IDP track record, but Dansby will reportedly be manning the MIKE slot on South Beach, making Dansby a solid IDP LB2 for the 2012 campaign. Burnett, on the other hand, will be playing in the 4-3 for the first time in his professional career, and that transition coupled with the fact that 2011 was the first time that the 29-year-old has topped 100 stops in his eight-year NFL career is enough to drop Burnett's fantasy value. However, he should, at the very least, maintain IDP LB4 value, which makes Burnett a player worth targeting in deeper IDP leagues given that he's presently being drafted well outside the Top 50 players at his position. Indianapolis Colts We'll conclude our tour of defensive dustups with a trip to scenic Indianapolis, where first-year head coach Chuck Pagano and the Colts are beginning the post-Peyton Manning era by blowing up the team on both sides of the ball. Pagano and new defensive coordinator Greg Manusky are instituting a "hybrid" 3-4 defensive front similar to the one employed by Pagano during his time with the Baltimore Ravens, and while the previous two defensive switches we've detailed were good news for the fantasy fortunes of the defensive linemen involved, the same cannot be said in Indianapolis. Robert Mathis, who finished among the Top 15 IDP defensive linemen each of the past four seasons, has already been reclassified as a linebacker by MyFantasyLeague.com due to his changing role in the Colts' new defense. If Mathis maintains positional eligibility as a defensive lineman in your fantasy provider, he will retain significant IDP value as a DL2, but a switch to linebacker drops Mathis from every-week fantasy starter to deep-league flier in IDP leagues that award highly for sacks. Batterymate Dwight Freeney has maintained his defensive lineman eligibility to this point, but as training camp progresses that could potentially change, leaving the 32-year-old as no more than a risky DL4 pick that could turn out to be fool's gold given his uncertain role and relatively low tackle production. Third-year pro Pat Angerer exploded into IDP prominence in 2011 on the heels of 148 total tackles, and while the youngster will be playing in a 3-4 front for the first time and there may be some bumps in the road as he makes the adjustment, Angerer should still see boatloads of tackle opportunities, making the former IDP standout a high-end fantasy LB2 this season. Finally, fellow third-year player Kavell Conner will be making a transition of his own in 2012, moving inside to play alongside Angerer after topping 100 tackles from the weak side of the Indianapolis 4-3 last year. Conner is flying under the radar somewhat in the majority of IDP drafts to this point, but as such players as Navorro Bowman of the San Francisco 49ers showed a season ago, both inside linebackers in a 3-4 set are capable of IDP relevance, making Conner an intriguing "sleeper" pick of sorts as a linebacker capable of LB4 fantasy production that can be had on the cheap. For additional information on these pros and other Individual Defensive Players making changes in position, scheme, or both, be sure to checkout the IDP Team Preview Series at IDP Manor, the Fantasy Sharks IDP forum, and for the latest news on IDPs follow IDP Manor on Twitter.