The New England Patriots have undergone a significant amount of change this off-season.

While most eyes are on rookies Chandler Jones and Dont'a Hightower on the defensive side of the ball, Tom Brady is seeing a lot of pieces come and go around him. Even though those changes are somewhat more understated, they are nonetheless important.

Realistically the Patriots haven't built a championship caliber defense, despite the investment in the draft this year. They may have built a defense capable of being part of a Super Bowl winning side, but that is provided that they have an explosive offense to rely on.

Explosion is the key word for the 2012 Patriots.

On defense they need more explosive players to make game changing plays. On offense, Brandon Lloyd is expected to be the dynamic threat that was lacking last year at receiver. Lloyd's arrival is somewhat understated also as he should be a perfect fit in New England, but even he is not as overlooked as the changeover at running back.

It wasn't a major shock that BenJarvus Green-Ellis found a new home this off-season.

Green-Ellis was signed by the Cincinnati Bengals after four seasons of consistency lining up behind Brady. Green-Ellis' greatest aspect of his play was his ability to hold onto the football. In 802 total touches with the Patriots, he never once fumbled the ball.

The 26-year-old had 24 rushing touchdowns the past two seasons and averaged 4.0 yards per carry over all four years in Boston. As a complementary piece in the Patriots' offense however, Green-Ellis never made the desired impact to take this offense to an unstoppable level.

His longest rushing attempt last season was a measly 18 yards while his average got better as the game wore on. With his first 10 carries, Green Ellis averaged 3.7 yards per carry but from 21-30, he averaged 4.3 yards per carry.

There is no doubt that Green-Ellis is a good football player, but he benefited more from the Patriots offense than he actually added to it.

A major reason why he didn't fumble the ball is because Green-Ellis faced more defensive backs than any feature back ever would. In the Patriots pass first offense, teams were too scared to play extra linebackers or defensive linemen, or even simply their base defense, because of the mismatch issues with Rob Gronkowski and Aaron Hernandez.

Green-Ellis didn't have the explosion to take advantage of his situation fully. The reason his average improves as the carries pile up is because he wasn't taking hits from linebackers early on. There is no doubt that he has the ability to wear down a defense, but that really isn't what the Patriots needed.

This year, Stevan Ridley should feature more prominently in the Patriots' backfield.

Ridley is maybe less reliable than Green-Ellis with the football, and one could say that the Patriots will really regret losing that aspect of Green-Ellis game because the most important thing for them recently has been to not lose the game running the football.

While he doesn't have the iron-clad grip, he should take advantage of the same benefits that Green-Ellis was afforded. In 90 touches as a rookie, Ridley fumbled the ball once. Of those 90 touches, 87 were rushing attempts with which Ridley averaged a mammoth 5.1 yards per game.

Unlike Green-Ellis' long of 18 yards for the season, Ridley managed a 33 yard touchdown run against the Oakland Raiders for his season long. Not only was that run longer than Green-Ellis' best, he also posted runs of 25, 24, 21 and 18 yards. Considering he had 91 less rushing attempts, Ridley's explosion is obviously greater than Green-Ellis.

On the field it's also easy to see how much better Ridley is in open space. He has the speed to break away from defenders but also the strength to shed tacklers trying to pull him down with their arms. He's not Darren Sproles or Reggie Bush, but there is a certain similarity in style to Fred Jackson of the Buffalo Bills.

Ridley won't wear down linebackers and defensive linemen, but he will be able to run over defensive backs on his way to hitting home-runs.

Ridley's biggest struggle as a rookie came in the redzone when he had only two first downs on 16 attempts and zero touchdowns. Fortunately for the Patriots however, they drafted Shane Vereen in last year's draft also.

Well, I say fortunately but really it's just a result of Bill Belichick's intelligence.

Vereen wasn't seen very much as a rookie but did have a touchdown carry against the Kansas City Chiefs in Week 11. On a four yard run off left end, Vereen showed a similar style to that of Green-Ellis.

He isn't very tall, or even that stocky, but his low center of gravity will benefit him in the NFL while he proved to be a powerful and intelligent runner in college. Vereen can make plays in tight spaces to properly complement Ridley while the veteran presence of Joseph Addai has also been brought in by Belichick.

Addai is an underrated runner who should still be able to make plays for the Patriots, but his real value will come in the passing game. Addai and Danny Woodhead will compete for the third down role for the team, but Addai may have the edge as he is a better pass protector.

The running backs aren't the only issue with the Patriots rushing attack however. This year, they should look to run the ball more, at least initially as the offensive line needs to establish itself.

Matt Light has retired, while Logan Mankins may or may not be ready for the start of the season. If Mankins can't go, then Robert Gallery will most likely join Nate Solder as a whole new left side of the line.

Solder may be very talented, but there is a major difference between being a bit part player as a rookie and Tom Brady's blindside protector for a whole season. Solder is a big body who may need time to find his comfort zone at the position. Like most linemen, Solder's comfort zone comes in the running game.

To help Solder adjust, and Robert Gallery who is a much better run blocker than pass protector, the Patriots will likely repeatedly look to establish the run even more than they did last year, despite having so many new weapons outside.

With Solder and possibly Gallery playing, the Patriots also need to find out just how much Brian Waters has left. Waters is undoubtedly living on borrowed time despite his good season last year. His performances dipped as the season went on last year, hopefully for the Patriots, that is not an omen for this year.

Only time will tell if the Patriots' newfound explosion in the backfield will be better or worse than their consistency from the past few seasons. One thing is for sure however, the wide receivers aren't the only ones with a new look on offense this year.