It isn't uncommon for managers to take center stage in soccer. They are, after all, in charge in a sport dictated by tactics. What is unusual, however, is for so many of them to command so much attention this early in the year, and for such a panoply of reasons, following an offseason with a rare amount of turnover among top-tier managers.

As the UEFA Champions League gets into its second round of group stage play - all televised live on the FOX family of networks - the storylines surrounding a slew of compelling matchups revolve around their managers.

Top billing goes to Celtic - Barcelona (FOX Sports 1, 2 P.M. ET), a rematch of perhaps the biggest upset of the last few years in continental play. As you'll recall, Barca overran the Hoops for the entire game last year, but were undone by goals from Victor Wanyama and Tony Watt, then making his continental debut. It was too much for Lionel Messi's stoppage-time tally to overcome. The crowd belted out "Fields of Athenry," and the game foretold the ultimate failure of the favorites' European campaign.

This time around, Tito Vilanova is out as Barca manager. So too is his sometime stand-in Jordi Roura. Vilanova's cancer treatments proved irreconcilable with his work. Tata Martino is in charge now, with Roura back in his old role as his assistant. But if Martino's Barca is a perfect 7-0-0 in the league and rolled over Ajax 4-0 in a dominant second half in their Champions League opener, questions are being asked about the style underpinning those scores.

He's in charge of Barca now, after all, where form matters much - certainly more than when Martino managed Paraguay at the 2010 World Cup, where he overachieved by reaching the quarterfinals, but did so playing unsightly soccer. Three weekends ago, Barca beat Rayo Vallecano 4-0 but, for the first time in five years and 317 games, had less possession than their opponents. To the fans of the possession-obsessed little virtuosos, this is akin to blasphemy. And with a public concession from defender Gerard Pique that Martino is indeed trying to mix up Barca's house style with a little more direct soccer, he has put himself on a collision course with the club's ideology and sense of identity. Against Celtic, as direct a team as you'll find, it bears watching if Barca matches those tactics or reverts to its foundational philosophy.

Steaua Bucharest hosts Chelsea (FOX Sports 2, 2 P.M. ET) in what would seem like an easy three points for the Blues, but then you would have thought that of their first European game as well, when they lost 2-1 at home to FC Basel. Prodigal son Jose Mourinho has returned to manage Chelsea for a second spell. But this time around, he isn't finding it quite so easy to make an impact. The club and its fans are accustomed to success now, and the tolerance for his antics is much reduced. His hoarding of wondrous attacking midfielders - Oscar and Juan Mata and Andre Schurrle and Willian, oh my! - has created a problem as all are plainly too good, and too expensive, to take place on the bench. One of those midfielders, Eden Hazard, will miss the game after an injury in training. And after winning just three of six league games, his relationship with the English press, which he thought would "respect and treat him fairly," is growing fractious.

Arsenal faces Napoli at home in London (FOX Soccer Plus, 2 P.M. ET) and here, too, the narrative arcs toward the men on the sidelines before it does to those on the field. Having spent several seasons mired in a relative mediocrity and after eight years of winning diddly-squat, Arsene Wenger's 17-year run at Arsenal looked like it would soon be up. But with a single player acquisition - Real Madrid 's inexplicably expendable Mesut Ozil - Arsenal has rediscovered that fluidity of yore. As a result, the Gunners have raced out to first place while impressively beating Olympique Marseille 2-1 away in Europe.

Rafa Benitez, meanwhile, was an unpopular and largely unsuccessful man in his stints with Inter Milan and Chelsea, after a triumphant run at Liverpool . He, too, seemed a bit washed up. Yet Napoli has hummed along this season, going undefeated in Serie A, including an away win at AC Milan , and, more significant still, a convincing 2-1 win over vice-European champions Borussia Dortmund at home.

In that game, Dortmund's own boss, the noted charmer Jurgen Klopp, lost his cool in spectacular, GIF-inducing manner at the referees' failure to get his defender back on the field in time to prevent a goal. That means he'll have to watch their home tie with Olympique Marseille from the stands, which shouldn't stop it from sparkling with attacking talent.

When AC Milan travels to Amsterdam to take on Ajax, meanwhile, Massimiliano Allegri will hope to build on his side's 2-0 win over Celtic two weeks ago. The Rossoneri's 2-2-2 start to the domestic season will hardly have left his employers impressed, following the debacle that was the bulk of their last season. In the opposite dugout, Frank de Boer, one of the hot young managers in the game, knows that a fourth consecutive tough draw will hardly serve as an excuse if he fails to finally advance to the knockout rounds. And if he suffers a second defeat, the hopes thereof are all but lost.