Two teams come to mind: the Philadelphia Eagles and New Orleans Saints.

It's hard to remember another team that's made as many changes in one offseason as the Eagles did this year. And there are questions around so many of the players they added. Can DeMarco Murray perform at a high level without the benefit of running behind the Cowboys' monstrous offensive line? I like rookie receiver Nelson Agholor a lot, but he's also never played an NFL snap. And then, of course, there's quarterback Sam Bradford, who has promise -- promise that he famously has yet to really fulfill.

Then there are the Saints, who traded away two significant offensive pieces in premier tight end Jimmy Graham and big-play threat Kenny Stills; what will this one-time aerial juggernaut look like in 2015? The defense, which was abysmal in 2014 after a not-bad 2013, has plenty to answer for. Finally, there's the matter of the team regaining its dominance at home. Unbeatable in New Orleans for much of recent history, the Saints lost an unimaginable five games at the Superdome last season. There are a lot of teams that you could pick here, but I'm going with the San Francisco 49ers, who have experienced an offseason of great change -- on both sides of the ball. They have a first-time head coach in Jim Tomsula and new offensive and defensive coordinators, too.

Lots of changes and questions. Where is Colin Kaepernick in his career? On offense, the line, which had been a strength of the team in the past, slipped last year in its performance and will be without longtime starters Anthony Davis (retirement) and Mike Iupati (free agency). Frank Gore has been replaced by second-year runner Carlos Hyde as the No. 1 back. On defense, top-flight starters Justin Smith and Patrick Willis (both retired) are gone, as are other key contributors.

Factor all of these changes together, and it's just so difficult to get a feel for how the Niners will be this season. Dear Bills,

I've tried to forget about you; it's not going very well. Your depressing quarterback situation pollutes so much of your promise, but I still can't quit you. Your defense is insanely good (first in sacks and fourth overall last year), and it should only improve with Rex Ryan. New offensive coordinator Greg Roman and offseason addition LeSean McCoy will resuscitate what was the 25th-ranked rushing offense in 2014. And you finally have a capable tight end on the roster in Charles Clay. Plus, Sammy Watkins put up 982 yards and six touchdowns with questionable quarterback play last year. He will do it again (probably) with a respectable run game in place.

Yet I still worry. The run blocking was a horror show last season. John Miller, one of the projected starting guards, has yet to take an NFL snap. Richie Incognito wasn't even in the league in 2014. The pass protection was a mess and Percy Harvin is a wild card.

Can a nine-win team really improve without upgrading the quarterback? I wonder.

That handsome logo and uniform can only take you so far.

Yours,

Colleen The league has never been more unpredictable, a quality found in abundance in the New Orleans Saints.

[My crash-and-burn Super Bowl pick from one year ago](http://www.nfl.com/news/story/0ap3000000385858/article/around-the-nfls-final-four-super-bowl-predictions), coach Sean Payton's team floundered to a 7-9 mark that had plenty to do with a junky, porous defense that gave up the fifth-most points in the NFL.

I like the look of this team heading into camp because of the (presumed) offensive transformation from a high-flying air show to a clock-chewing, run-heavy squad set to pound teams with Mark Ingram and scorch 'em with C.J. Spiller. A cast of new wideouts will angle to make up for the loss of tight end Jimmy Graham, but that burden also falls on "Making the Leap" candidate Josh Hill. One way or another, I like the idea of Drew Brees in a ground-centered attack as we saw with Tony Romo and the Cowboys last season.

Still, this defense remains foggy enough to sideswipe a squad that feels like a playoff team on paper (but only if everything goes perfectly right). The Dallas Cowboys are the toughest team for me to read heading into training camp. On paper, this team looks like a title contender in the NFC. These 'Boys are built to make a deep postseason run behind a powerful offense that features a franchise quarterback ( Tony Romo), big-play receiver ( Dez Bryant) and a dominant offensive line. Although there are questions at running back, the physicality of the front five should allow ANY runner to have success on the ground. On defense, Greg Hardy and Randy Gregory upgrade the Cowboys' pass rush while first-round pick Byron Jones should improve the team's coverage in the back end.

Despite those moves, I'm reluctant to go "all in" on the Cowboys because they typically underachieve when they are anointed the favorites heading into the season. Last year, they were able to sneak up on opponents as an underdog. But this season, everyone will use Dallas as a measuring stick, giving the 'Boys their best effort each week. The pressure is vastly different when you're the favorite, and I'm not convinced the Cowboys are mentally tough enough to withstand it.

From a tactical standpoint, I worry about the loss of Bill Callahan and how his absence will impact the play of the offensive line. He did a great job developing the Cowboys' young front; I wonder if his successor, Frank Pollack, can keep this development going. Finally, I still have reservations about the Cowboys' defense. The unit plays hard and flies around the ball, but I wonder if the Cowboys can continue to win with a simplistic scheme (over cover 1) that's a staple in high school play books. Rod Marinelli did a great job of getting his guys to outwork opponents last year, but can he get the group to heed his message with everyone touting them as Super Bowl contenders?