The Europa League kicks off Thursday under a cloud of controversy, with 24 matches and some surprising names making bows in Europe's second-tier club competition.

Notable clubs taking part this year include Glasgow Celtic, Paris Saint-Germain, Fulham, Atletico Madrid, Birmingham City, Stoke, Dynamo Kiev and Tottenham Hotspur. At least one of those teams sees the game as little more than a "nuisance" and left one of their best players off the roster; another is the subject of a lawsuit over its participation; and a third's presence is tainted by allegations of money laundering -- and the fact that the team was relegated last season.

Let's start with Celtic, which lost a playoff to Sion, but were re-instated after UEFA adjudged that the Swiss side used ineligible players in defiance of a FIFA-imposed transfer ban. Sion's colorful president Christian Constantin has run afoul of football administrators in the past; in the wake of UEFA's decision Tuesday, he called UEFA president Michel Platini a criminal who should "be jailed."

Despite the hyperbole, the fact is that Sion won a judgment in Swiss court that explicitly ordered UEFA to reinstate the team, muddying the waters a bit. Teams are not allowed to challenge UEFA or FIFA in local courts, but Sion is determined to set a precedent, noting that UEFA and FIFA reside on Swiss soil. The case now moves to the Court of Arbitration for Sport, which has the power to reinstate Sion or award compensation.

Celtic, meanwhile, will face Atletico Madrid in Spain and may be catching the Spaniards at the right time: Atletico failed to score in either of their opening La Liga matches but do have a full-strength squad to call upon, including gaudy new signing Radamel Falcao, pried from last year's Europa League winner FC Porto. Celtic sit just a point back from Rangers in the Scottish Premier League with only a single loss in league play to date, but they face their arch rival Sunday in an Old Firm clash just 72 hours after this European assignment.

Then there's Tottenham, a club off to a dismal start in England that has to play Liverpool on Sunday. They travel to Greece to face PAOK missing at least nine regulars including the omitted Rafael van der Vaart and the injury-hit William Gallas, Michael Dawson, Sandro and Tom Huddlestone. Van der Vaart, who has been sidelined with a hamstring injury, wasn't happy about being left off the European roster, unleashing a tirade on his personal website under the headline "annoying."

Birmingham are making their first bow in Europe in 50 years (despite being relegated from the Premiership last year) by virtue of their shock Carling Cup win over Arsenal. By rights their home game against Braga should be cause for celebration. But the legal troubles of their owner Carson Yeung have added a nasty tinge to what has already been an erratic year for the Blues. Yeung has been jailed in Hong Kong on charges of money laundering and the freezing of his assets meant that the club had to conduct a player fire sale to keep the gates open. The result? The Blues have only two wins so far, including a badly-needed 3-0 victory against Milwall on the weekend that finally hauled them out of the Championship's drop zone.

One club who are delighted to be in Europe are Stoke, the oldest club in the Premier League, making a return to what used to be called the UEFA Cup for the first time in 37 long years. In 1974, they were bounced out by Ajax on the away goals rule after failing to score in their home leg. Now, after a busy transfer window that saw them pick up some quality in Wilson Palacios and Peter Crouch, the Potters look like they can make a serious run. They face a difficult trip to Ukraine to face Dynamo but are in a winnable group that includes Besiktas and Maccabi Tel-Aviv. Tony Pulis's team is also fresh off a massive 1-0 win over Liverpool that showcased their defensive organization and left them sitting a surprising 5th in the Prem.

Finally, newly wealthy PSG will be making a big run at a trophy as they host minnows Red Bull Salzburg at the Parc des Princes. They spent an astonishing $122 million to reinforce their squad, plucking Kevin Gameiro, Blaise Matuidi, Diego Lugano and a real whopper in Javier Pastore for an eye-popping $59 million from Palermo. PSG are off to a solid start in what is becoming an intensely competitive Ligue 1 , tied for third on points with Lille. They are arguably the team to keep an eye on.

One other thing to remember about the Europa League: after the group stage ends and 24 teams advance, there are eight additional participants for a knockout stage that includes third place Champions League group finishers that "drop" into the EL. That could mean the likes of a Napoli or an Arsenal showing up when the competition really heats up.