They say there's always room for improvement, and that adage certainly rings true in the NFL.
For a variety of teams, the improvement needed is minimal. For others, considerable upgrades must be made.
Here's a look at the organizations who improved specific positional groupings the most heading into the 2013 campaign.
Last year, four Arizona Cardinals quarterbacks—Kevin Kolb, John Skelton, Ryan Lindley and Brian Hoyer— combined for a cringe-worthy average passer rating of 63.1.
That's not good.
After a vast organization overhaul to begin the calendar year, new general manager Steve Keim signed quarterback Carson Palmer to lead Bruce Arians' downfield passing attack.
Palmer threw for 4,018 yards with 22 touchdowns and 14 interceptions on a sub-par Oakland Raiders team a season ago, and if protected, he should be a massive upgrade from the dreadful quartet of signal-callers Arizona had under center in 2012.
Honorable mention: Kansas City Chiefs
The Cardinals struggled to get viable play from their quarterbacks in 2012, but that wasn't their only offensive problem.
As a team, Arizona compiled a league-low 1,204 rushing yards at a 3.4 yards-per-carry clip, the worst average in football.
In an attempt to alleviate the ground-game issue, the Cardinals snagged free-agent Rashard Mendenhall.
At 5'11'' and a rocked-up 210 pounds with deceptive speed and agility, the former Pittsburgh Steelers runner has a feature-back skill set.
If Mendenhall can stay healthy, he should shoulder the lions share of the carries for the Cardinals.
Beyond him, Stepfan Taylor, a rugged, between-the-tackles back from Stanford was added in Round 5 of the draft.
Speedy scat back Andre Ellington was selected in Round 7, much later than many expected him to be picked.
With three new runners in the backfield, the Cardinals greatly improved the skill aspect of their running game.
Honorable mention: Green Bay Packers
There's reason to be a bit concerned with Tavon Austin's size, but he was the most dynamic play-maker in the draft, and he'll be used on a variety of high-percentage passes for Sam Bradford, something the veteran quarterback needs.
Steadman Bailey isn't as electric in the open field as his West Virginia teammate, but he possesses a refined set of receiving skills and should contribute instantly.
St. Louis' wideout contingent struck little-to-no fear into opposing secondaries a season ago after Danny Amendola was lost for the year. Now, the additions of Austin and Bailey have totally flipped the script.
Honorable mention: Buffalo Bills
With the hiring of Chip Kelly came a multitude of intriguing, low-risk free-agent signings.
One of them was H-back, fullback, tight end—whatever you want to call him—James Casey.
About as versatile as they come, Casey's receiving statistics have improved across the board in all four of his seasons in the NFL.
In 2012, he snagged 45 passes for 330 yards with three scores, and at 6'3'' and 245 pounds, the former Houston Texan can play fullback if need be.
Second-round pick Zach Ertz has major pass-catching ability from the same H-back position at 6'5'' and 249 pounds.
He had 112 receptions for 1,434 yards and 15 touchdowns in his three-year Stanford career.
Brent Celek is already in place as the team's primary tight end, but the acquisitions of Casey and Ertz will give the Philadelphia Eagles a major, passing-game boost.
Honorable mention: Chicago Bears
Chris Johnson got off to an atrocious start last year, running for 45 yards in his first 33 rushing attempts of the season.
He played relatively well the rest of the way, and thanks to a handful of long runs, Johnson ended 2012 with an efficient yards-per-carry average of 4.7.
However, more offensive line fortification was needed, especially with younger Jake Locker under center.
Offensive lineman Andy Levitre was the team's first huge splash in free agency, and although he's not a road-grading guard, he's fleet-of-foot, plays fundamentally sound—especially as a pass-blocker—and is extremely durable.
As if his acquisition wasn't enough on the interior, the dominating Chance Warmack was selected in the first round.
The presence of Levitre and Warmack should benefit Johnson and Locker a great deal in 2013 and beyond.
Offensive line: Philadelphia Eagles
The Cleveland Browns revamped their defensive line in a significant way this offseason.
Although Paul Kruger was the big-name free-agent acquisition—a guy who accumulated nine sacks during the 2012 regular season—Desmond Bryant was a lower profile addition that will pay huge dividends for Rob Chudzinski's squadron.
ProFootballFocus.com (subscription required) gave Bryant an overall grade of 16.5 during the 2012 season, which was the sixth-highest grade of any defensive tackle who played at least 25 percent of his respective team's snaps.
Furthermore, LSU's speedy edge-rushing specialist Barkevious Mingo was snagged in Round 1 of the draft.
Those three skilled defensive linemen—Mingo will play some outside linebacker—makes the Browns much more intimidating upfront.
Honorable mention: Detroit Lions
Cheating here a little, yes.
Because no team stood out in terms of upgrading its linebacker corps with new players this offseason, the Dallas Cowboys get the nod here, thanks to veterans who'll return from 2012 injuries.
Sean Lee has the talent to become one of the game's most prolific middle linebackers—a true stud in coverage and when attacking the line of scrimmage—and Bruce Carter exudes athleticism from his weakside spot.
Both missed considerable time last year but should be featured pieces in Monte Kiffin's 4-3 scheme.
Justin Durant isn't an elite strongside linebacker, but he did total 103 tackles a season ago with the Detroit Lions, and he excels against the run.
Honorable mention: Arizona Cardinals
The absolute no-brainer of all no-brainers.
If he returns to pre-injury form, Darrelle Revis will be the most effective cornerback in football. Dashon Goldson isn't a Top 5 safety, but he has a reputation as an exceptionally hard hitter, and he reeled in nine interceptions over the last two years with the San Francisco 49ers.
Add in second-round pick Johnthan Banks, who was a feisty ballhawk at Mississippi State, and it's easy to realize that no secondary improved more than Tampa Bay's this offseason.
Remember, the Buccaneers allowed 297 yards through the air and an average QB rating of 93.5 in 2012.
Honorable mention: Atlanta Falcons