When the Baltimore Ravens and New York Giants won two of the past three Super Bowls, their quarterbacks shredded playoff opponents for a combined 20 touchdown passes with just one interception. It was a beautiful thing to watch unless your team was on the losing end, but now the beauty is a faded memory. Those same quarterbacks have combined for more picks (64) than TD passes (63) since winning it all, and now both teams are hoping new offensive coordinators can orchestrate turnarounds.

"Baltimore is very intriguing to me with Gary Kubiak and a pretty good quarterback," an offensive coordinator from another team said recently.

It's that time of year in the NFL. Since last season, 21 of the 64 offensive and defensive coordinator jobs have turned over. As teams work their way through organized team activities, coaches and executives around the league are forming early opinions. Some newly hired coordinators have big shoes to fill (think Paul Guenther in Cincinnati or Frank Reich in San Diego). Others are preceded by their reputations.

I've singled out five compelling coordinator changes for a closer look through the eyes of league insiders: Kubiak in Baltimore, Ben McAdoo with the Giants, Ray Horton in Tennessee, Kyle Shanahan in Cleveland, and Gregg Williams in St. Louis. Which ones will produce the desired results?

1. Kubiak to the Ravens as offensive coordinator

Quarterback Joe Flacco is ditching the three-digit play system for West Coast terminology and expanded zone concepts with the bootleg action Kubiak used when Matt Schaub was his quarterback in Houston. We won't know until the season starts whether this will be a full or partial conversion. Sometimes, a new coordinator adjusts not only to his personnel but to the preferences of the head coach. Kubiak, as a longtime former head coach, is more established than the majority of coordinators. A similarly established offensive coach from another team said he thought that could be a very good thing in Baltimore.

"I am a huge Kubiak fan," that coach said. "In my opinion, Flacco is controlling too many things there. You need to grab ahold of him and tell him to just go play. He's had the keys to the car and hasn't gotten it started, so Kubiak needs to say, 'Here is what we are going to do.' I think Kubiak can do that."

A former personnel director working in another capacity wasn't so sure. "I think Flacco is what Flacco is -- he doesn't care," the ex-director said. "He will do what he wants to do. Look at how he handled the contract negotiations. You've gotta be careful how much you're going to change him, I would think."

Opinions are all over the map. One general manager questioned whether the towering Flacco was a good fit for what Kubiak wants to run. Others suggested Flacco's athleticism is underrated and that he'll be fine in the system. The GM who questioned Flacco's fit in the offense said he thought Ray Rice could flourish with the concepts Kubiak prefers, while a coordinator who thought Rice looked old last season expected Kubiak's offense to help spring receiver Torrey Smith on deeper routes.

We might expect more of an intermediate and shorter passing game from the Ravens, a subject we'll revisit in the section on the Giants. In the past four seasons, Baltimore ranked second in air yards per pass attempt, which reflects how far the ball travels past the line of scrimmage to its target on average. Kubiak's Texans were 27th in that category during the same period. Baltimore was sixth and Houston last when play-action passes were removed from the equation. Some of that could reflect differences in personnel, specifically at quarterback. Scheme was also a factor to some degree.

2. Ben McAdoo to the Giants as offensive coordinator

The Giants had the same quarterback and offensive system from 2004 through last season. McAdoo's hiring from the Green Bay Packers means Eli Manning will join Matt Ryan, Philip Rivers and Ben Roethlisberger as veteran quarterbacks changing systems after long runs of schematic continuity. A lot of others -- Peyton Manning, Aaron Rodgers, Drew Brees, Tom Brady and Tony Romo come to mind -- remain in the same systems they mastered years ago. The question with the Giants is whether we should buy the narrative that change is good -- that it will "energize" an older quarterback whose career has stagnated.

"If they start 1-4, the energy will be gone and Tom Coughlin will tell them to put in new plays," one veteran assistant coach cracked.

Learning the new offense isn't going to be a problem for Eli Manning even after a decade in the system Kevin Gilbride coordinated for the Giants. One head coach described Manning as "off-the-charts brilliant" and smarter than his brother Peyton. The fact that Manning has recovered from ankle surgery well enough to participate in OTAs is another bonus on the preparation front.

"McAdoo will give them different concepts in the passing game -- shorter passes to supplement the running game and more midrange routes to move the chains," a personnel evaluator familiar with McAdoo predicted. "The tight end will be a big part of that, too. In that type of offense, you cannot have enough tight ends who can play multiple spots. Also, in that offense, you can maybe take one, two deep shots a half, but really emphasize the short and midrange throws. Run after the catch will be big for them."

The air-yards stats could be telling here. The Giants have led the NFL with a 9.5-yard average since 2011. The Packers were 23rd at 8.0 in the same period. The figures since 2008 have been 9.2 for the Giants (first) and 8.4 for the Packers (13th, near the league average).

"I think some of the Green Bay stuff will be refreshing for Eli," a coordinator with NFC North experience said. "Tom [Coughlin] still has a healthy respect for running the ball, which they did in Green Bay when they had runners. They used to like to run it up your tail if they could."

My feeling is that Manning's interception totals were going to decline anyway, and that an offense focusing on shorter passes could help facilitate this. Pass protection is the key variable more than scheme. The Giants cannot help but be better on that front.

3. Ray Horton to the Titans as defensive coordinator

Horton traces his coaching roots to Pittsburgh, home of a more traditional 3-4 defense. A pro personnel director didn't see the fit in Tennessee, suggesting the Titans' personnel wasn't great for a 4-3 and would be worse for a 3-4. We've even heard the word "hybrid" used in relation to the defense Horton plans to run, but this is a case where labels can cloud our understanding more than they bring clarity.

"It's really a 3-4 under defense, which they played some in Tennessee last year even though they had 4-3 personnel," one coach explained. "And then teams are playing sub packages 60 percent of the time, anyway, and there is no difference. You're playing a four-man front, same as everybody."

Outside linebacker Kamerion Wimbley could be the biggest beneficiary of the scheme change. He played only 343 snaps last season, down from at least 870 in each of his previous five seasons with Tennessee, Oakland and Cleveland. The Titans will need Wimbley and strongside linebacker Derrick Morgan to rush off the edge from within their sub packages. One key to their potential success in the base defense will be for Horton to help create mismatches for Wimbley and Graham against tight ends and running backs.

Defensive tackle Jurrell Casey, who broke out last season with 10.5 sacks as a three-technique defensive tackle, is not suddenly going to become a two-gapping plugger under Horton. His versatility will be key to continued success in the new defense.

"Horton, when he was in Cleveland, gave us all we wanted," an opposing offensive coordinator said. "He is really good."

4. Kyle Shanahan to the Browns as offensive coordinator

The feeling among most is that Shanahan is a great fit for the Browns and quarterback Johnny Manziel because Shanahan will be willing to tailor the offense for an unconventional quarterback. His background would also allow for tailoring a more traditional offense for a more conventional QB such as Brian Hoyer.

The bigger questions are how quickly Manziel will find his way into the lineup and whether he'll remain healthy enough or productive enough to hold onto the starting job as a rookie.

Fourteen of the past 16 quarterbacks taken in the first round have started more than half of their teams' games as rookies, and it's virtually impossible to envision Manziel staying on the bench for long.

"Manziel is raw," one offensive coach said. "He really does want to learn, but he has no idea about protections, and a lot of the young quarterbacks are in the same situation. They do not know coverages. They have really just played a half-field throwing game. Shanahan can get Manziel going because he knows the spread game. [Robert Griffin III] could do what they wanted him to do [in Washington] and do it well before he got hurt."

Quarterbacks tend to make receivers, not the other way around, but Josh Gordon led the NFL in receiving yards (1,646) and was second among qualifying players in yards per catch (18.9) for the Browns last season while catching passes from Hoyer, Jason Campbell and Brandon Weeden. The possibility of Gordon serving a one-year suspension casts a shadow on expectations.

"With Kyle, it is hard to know what he is working with," an offensive coordinator said. "Gordon is a very talented, talented guy, but it sounds to me like he is out, and that kills you."

5. Gregg Williams to the Rams as defensive coordinator

The Rams wanted a veteran defensive coordinator last offseason when they made a run at Rob Ryan and appeared very close to landing him. That move did not work out. The team went with a first-time coordinator instead, with disappointing results. Williams was the veteran coordinator St. Louis wanted in the first place, long before Ryan entered the picture. He has a long history with coach Jeff Fisher and is walking into a team featuring four early first-round draft choices on the defensive line.

"Gregg Williams is a nightmare coaching with St. Louis because they have a great front," an offensive coordinator said. "He has multiple packages. It will not be just those guys sitting in a straight 4-3. They will be kicking them and moving them. Now they also have an inside rusher with the kid they drafted."

The Rams have big expectations for rookie defensive tackle Aaron Donald on a line already featuring Robert Quinn, Chris Long, Michael Brockers and William Hayes. St. Louis leads the NFL in sacks during the past two seasons, but the Rams rank only 17th in Total QBR allowed and 23rd in passer rating allowed. The expectation here is that Williams will close that gap.