In OTAs (Offseason Talk & Analysis) all through June, the Sports on Earth NFL team will break down each team's offseason transactions, boldest moves and burning questions as they prepare for training camp.

Rebuilding is such a loaded word. The Falcons are renovating, or retooling, or even restoring an infrastructure that crumbled last season. The Matt Ryan/Julio Jones façade will remain standing throughout the construction project, but just about everything else is under hardhat conditions. The Falcons are rethinking their strategies while getting far, far younger on both sides of the ball. It's bound to pay off in the long run, but for the Falcons to compete in 2014, lots of youngsters must step up, and a handful of veteran free agents must set a whole new tone on defense.

Biggest Move: The Defensive Shift from a 4-3 to a …

Don't call it a 3-4 defense! Neither Mike Smith nor Mike Nolan wants the Falcons defense labeled. So ignore the fact that the Falcons signed and drafted several players perfect for a 3-4 scheme: 330-plus-pound tackle Paul Soliai; massive five-tech, two-gap specialist end Tyson Jackson; and supersized rookie lineman Ra'Shede Hageman, who looks like the ideal 3-4 blocker gobbler.

We all know that 3-4 and 4-3 are outdated football concepts anyway, like "running to set up the pass." The Mikes like to be multiple, and now they have the personnel to do it. The newcomers on the line join Jonathan Babineaux to give the Falcons the beef they lacked as last season descended into a winter of broken tackles and unpressured quarterbacks. Kroy Biermann returns from an Achilles injury as an excellent hybrid defense multi-tool -- call him a defensive end who drops into coverage well or a big linebacker who can set the edge, just don't pigeonhole him. Neither Jonathan Massaquoi nor Osi Umenyiora is an ideal every-down defensive end (those days are behind Osi), but mix-and-match them in multiple fronts and they can still bring the pressure.

The buzzword in Atlanta this offseason has been "toughness," in part because the Falcons allowed the third-highest broken tackle rate in the NFL last season (via Football Outsiders). Talent is as important as toughness, and three newcomers -- plus the return of Biermann -- give the Falcons both the big-dude athleticism they need and a dose of girth and grit. It doesn't matter if the Mikes call their defense a 4-3 or 3-4; they just need seven defenders they can truly trust.

Biggest Gamble: Trusting Toilolo

Tony Gonzalez is irreplaceable. But that does not mean the Falcons should not have tried. The team ignored the tight end position in the draft and free agency, leaving the job to Levine Toilolo, an NBA forward-shaped novice who caught just 11 passes for 55 yards and two touchdowns last season.

Toilolo is listed 6-foot-8, and it is easy to see his potential as a red-zone post-up specialist. He had his goal-line moments last year, including a corner-of-the-end-zone reception with Jets safety Dawan Landry draped all over him. But Toilolo did not see much playing time for a team that grew desperately short on passing weapons as injuries mounted. His production consisted mostly of three- to five-yard receptions in the flat from an H-back position. And opponents began to figure out his goal-line routine late in the year: The Cardinals jammed Toilolo hard whenever he called for a pass in the paint, and one attempt at a rollout touchdown resulted in a three-yard loss. Based on the 2013 game film, Toilolo is a lumbering project, not someone ready for a major role.

There is little behind Toilolo on the depth chart. Longtime Giants H-back Bear Pascoe is just that: a longtime H-back suitable for situational use. Mickey Shuler spent much of last season on the Falcons practice squad and is penciled in as Toilolo's primary backup. Shuler is either the guy who spent three seasons on the back of the Vikings and Dolphins benches or his father, who caught 438 passes for the Jets in the mid-'80s. Either Shuler is about equally effective these days.

Gonzo was targeted 121 times last year, second most of any tight end. (Jimmy Graham ranked first and does not like the term "tight end" very much). He caught 83 passes for 859 yards and eight touchdowns, ranking fourth in the NFL in Football Outsiders' DVOA metric for tight ends. Gonzo looked like he could play another three seasons, but he will not, no matter how many messages the Falcons leave on his cell phone. Toilolo must replace at least some of that production, and he is not going to do it by running four-yard flat routes and waiting in the end zone for entry passes.

Biggest Question: How young is too young on defense?

The arrivals of Jackson and Soliai and the return of Biermann provide a veteran presence for a defense that really needs one. The Falcons are expected to start at least four second-year players, including three-fourths of their secondary: cornerbacks Desmond Trufant and Robert Alford, safety Zeke Motta and linebacker Paul Worrilow. Dig deeper into the depth chart and you find an even bigger crop of rookies and sophomores competing for significant roles: Hageman and Malliciah Goodwin on the defensive line, rookies Dezmen Southward and Ricardo Allen in the secondary, too many guys to mention at linebacker.

The Falcons insulated themselves against the possibility of getting too young, too fast. In addition to the experienced linemen, nickel defenders Josh Wilson and Javier Arenas are on hand to compete for jobs if the youngsters are not ready. And GM Thomas Dimitroff treated rookie free agency like it was the dollar audio cassette bin at a thrift store: no mid-round pick is getting handed a job after 20 rookie free agents were signed on both sides of the ball. Still, a defense that relies too much on youngsters can create a situation counterproductive to player development -- too many players doing too much too soon can cause bad habits. Wide gaps in zones can lead to missed open-field tackles or "freelancing" defenders abandoning assignments, and so on. For evidence, have a look at the 2013 Falcons defense.

The Falcons are doing the right thing by loading up on young talent, and all of the competition should pay dividends down the road. But there will be growing pains. Just how long those growing pains last will be a factor for both fans and Smith and Nolan, whose employment statuses depend on a (somewhat) quick return on the team's investments.

Bold Prediction

A rebuilding (renovating, whatever) project is no place for a 31-year old running back coming off injuries and a 3.5 yards-per-carry season. Look for Steven Jackson to give way to rookie Devonta Freeman sooner than later as the Falcons' featured running back, with Jacquizz Rodgers remaining in the change-up role. Freeman is a tackle-breaking tough guy, but his pass-protection ability will push him into an every-down role. Few rookies are as ready as Freeman to pick up blitzes when not taking off-tackle handoffs.