David Moyes had an impossible job. When Sir Alex Ferguson, undisputably the greatest manager in English soccer history, named Moyes his successor, there was nowhere for United to go but down. Despite winning the title last season, few believed they had a roster capable of competing with Manchester City or Chelsea. That opinion turned out to be spectacularly correct. (Of course, few thought much of Liverpool either, who are the clear favorites to take the title this May.) As has been speculated since roughly November, Moyes's first season at Old Trafford will be his last.

The Ferguson-Moyes transition is a fascinating study in managerial importance. How can a largely similar squad go from 89 points and a title to 57 points (with four matches remaining) and seventh place? Could a manager really make a 30-point difference?

The most striking difference between Ferguson's and Moyes's United is goals scored. United are scoring almost an entire goal fewer per game than last season, a drop from 2.26 to 1.43. Meanwhile, their goals allowed rate is nearly identical, at 1.17 this year compared to 1.13 under Ferguson. (All stats in this article via WhoScored.com.)

Obviously, Moyes's main problem was offensive, but anyone who has watched United this season knows that. How did their offense change last year to this year? To answer this, I looked at a few offensive categories on a per-game basis: shots, possession, pass success, crosses, through balls, and long balls on a year-over-year basis for each team. I compared United's year-over-year change to other contenders: Manchester United, Manchester City, Arsenal, Chelsea and Liverpool. (It should be noted that Manchester City and Chelsea have new managers this season as well.)

Man Utd Stats 1

Offensive Stats 2

The two changes that immediately jump out are pass success percentage and crosses. Out of the five teams, United is the only side to see a significant decline in pass success, a 2.4 percent drop from Ferguson's final season. The same observation holds for crosses per game, although the now-legendary 81-cross game against Fulham likely skews the numbers. Still, it doesn't seem logical to pin such a severe goal drop on hitting more crosses and a few extra missed passes.

As you might expect, a goal-per-game drop in scoring is likely the result of several factors. (If it was as simple as one thing, they probably would have fixed it.) Instead, Moyes's side has fewer successful passes, fewer shots, more low-percentage crosses and long balls and fewer high-yield through balls than the previous year's team. That is, United have been more reliant on low-percentage, low-yield attacks based on crosses and long balls than Ferguson's title-winning squad.

The question then becomes whether this is a symptom or a cause. Moyes has had to deal with more injuries than Ferguson in his final year, with the team's best goal scorer, Robin Van Persie, sidelined for much of the year. Van Persie's atypically healthy 2012-13 season is likely the primary reason United was able to cruise to the title: That year, he had the third-most shots per game and the most goals in the entire league. Wayne Rooney has roughly the same shot attempts per game this year, but 11 fewer goals to show for it.

Injuries aside, United lacked a creative midfielder for much of the season, with Shinji Kagawa often perplexingly relegated to benchwarmer (sparking the hashtag #FreeKagawa). Juan Mata joined the club during the January transfer window; in his brief time, his influence has been less than inspired. In Marouane Fellaini's 18 appearances since joining the club in September, he has no goals or assists, which still makes him sound more effective than he is.

Kagawa, Fellaini and Mata suggest that Moyes couldn't make it work at United, but this too prompts more questions than it answers. Fellaini scored 11 goals in the Premier League last year at Everton under Moyes, showing versatility and power he rarely demonstrated at United. Mata was one of the better attacking midfielders in the world last year, although he fell out of favor under Jose Mourinho at Chelsea prior to his transfer. Considering United didn't lose any important players over the offseason, it would be foolish to argue Moyes had less to work with, Van Persie injury aside.

The most likely explanation for Moyes's failure is more philosophical. In his 11 years at Everton, Moyes proved to be a capable manager, and certainly no idiot. But Moyes's prior success was of a very different nature, keeping a financially limited club in constant contention. United is a much different challenge: Turning diamonds into brighter, more expensive diamonds. This was something at which Ferguson excelled masterfully, constantly getting the most out of any given player.

There have been rumors that Moyes and Ryan Giggs, United's longest-tenured player and village elder, had a falling out. Before Ferguson announced his retirement, Robin Van Persie made it no secret he was joining United that year to play under Fergie, so it's not difficult to imagine Moyes's sudden entrance might have been a frustrating revelation. It's entirely possible the on-field difficulties were manifestations of off-field clashes.

The final explanation, however remote, is that Sir Alex Ferguson really is even more powerful than we could have possibly imagined. It's possible he really is worth 30 points to a club and, with a little luck, turned a mediocre United side into a title-winning squad. But, if you're a Red Devil, you should hope this isn't the case -- since, for whatever faults Moyes may have had, there won't be another Ferguson any time soon.