Move over, Peyton Manning. Stand aside, Alex Rodriguez.

The highest-salaried athlete in professional sports these days may be a Cameroonian soccer player named Samuel Eto'o, who will play his home games for an obscure club in the violence-wracked Caucasus region of Dagestan, Russia.

In a deal announced Tuesday, Anzhi Makhachkala of the Russian Premier League agreed to pay Eto'o's former club, Inter Milan, a transfer fee of $39 million to acquire the 30-year-old forward.

The team also agreed to a contract with the player that, given Russia's favorable tax rates, would net Eto'o $29 million per season. That not only eclipses the estimated $17.4 million salary Cristiano Ronaldo earns at Real Madrid, it also outstrips the net income of top U.S. stars like Manning, Rodriguez and Kobe Bryant.

The only athlete on earth who might pocket as much is Fernando Alonso, the Spanish Formula One driver for team Ferrari whose contract is worth more than $40 million per year.

"Today an agreement was reached between the football clubs Anzhi and Inter for the transfer of Samuel Eto'o," a statement on Anzhi's website said. "The terms of the transfer fully suited both sides."

The decision by Eto'o to leave Inter Milan, one of Europe's most hallowed professional teams, for an obscure mid-level team in Russia, is an unlikely one that leaves devout soccer fans scratching their heads.

Eto'o is a three-time Champions League winner. He was signed by Real Madrid at 16, scored more than 100 goals for FC Barcelona and is the most decorated African player of all time.

Chiseled and lightning fast with a laser-accurate shot, he's known as one of the sport's most prolific goal scorers.

By contrast, his new club plays in a second-rate league in a downtrodden stadium in front of an average crowd of 11,067. The Dagestan province has become a center of jihadi insurgency where shootouts between rebels and police are a nearly daily occurrence. For security reasons, Anzhi's high-profile players live in Moscow and only fly to Makhachkala for home games. In recent years the club has narrowly avoided relegation from Russia's top division.

The unlikely story behind soccer's richest transfer begins in January when Anzhi was bought by Suleiman Kerimov, an oil tycoon whose net worth is reported to be $7.8 billion. Kerimov, a Russian senator who was born in the southern republic of Dagestan, is a lover of elaborate parties and exotic sports cars. He once famously split a Ferrari Enzo in half in an accident in the south of France and lived to tell about it.

Upon taking control of the team, Kerimov vowed to turn Anzhi into a contender and, in doing so, help transform the region's reputation. In March, he lured Roberto Carlos, a World Cup winner with Brazil in 2002, to the club with an annual salary of $7.2 million and a Bugatti Veyron, which was given to to the veteran defender by Kerimov as part of a gala birthday party that cost an estimated $3 million. (The guest list included Anna Chapman, a Russian spy nabbed by U.S. authorities in 2010 who has since become a pinup in Russia.)

A handful of other promising acquisitions have followed, including fellow Brazilians Jucilei da Silva and Diego Tardelli and Hungarian winger Balasz Dzudszak, a $20 million signing from PSV Eindhoven.

Kerimov is also building a 45,000-seat stadium, hotels and a soccer training camp along the shores of the Caspian Sea near the capital that locals have called "Anzhi City." An official close to Mr. Kerimov said that the project will cost more than $1.5 billion in the next few years and "has a long-term character with two different aims—social and athletic."

"In the future, we hope to get to the championship league, but we clearly understand that it takes time and enormous work," the Kerimov official said. "Among our other aims is to prepare players for the Russian national team.

The influence of Russian money in European soccer is nothing new. Back in 2003, Roman Abramovich arrived in England's Premier League like a hurricane, plunking down $250 million to buy Chelsea and embarking on an unprecedented shopping spree that transformed the upstart club into one of Europe's powerhouses. Russia was also chosen to host soccer's World Cup in 2018, beating rival bids from England, Spain-Portugal and Belgium-Netherlands. Moscow hosted the Champions League final in 2008.

The deal for Eto'o points to a new reality in European soccer, one where midsize Russian clubs awash with money and backed by wealthy benefactors are threatening to transform the professional game at a time when new financial rules have forced even the wealthiest clubs to rein in spending.

Starting this season, European teams are bound by Financial Fair Play regulations, a series of measures introduced by UEFA, the governing body of European soccer, to prevent clubs from spending more than they earn in revenue. This season's accounts are the first that must be submitted to comply with the new rules, which come into force for the 2013-14 season.

As the sport's biggest teams curb spending, a series of star players has been bought by obscure teams in Eastern Europe for sums ranging from $62 million for a Portugese midfielder to $18 million for a manager.

In some respects, Eto'o's decision to swap the glamour of Milan for megabucks in Makhachkala is only the latest testament to the lengths athletes will go—and the indignities they will endure—in exchange for astronomical paychecks.

In the Russian Premier League, overseas stars have also been forced to endure racist slurs from opposing fans. The Russian Football Union has fined two teams nearly $11,000 apiece for incidents in which Anzhi's Roberto Carlos has been taunted with bananas.

Not everyone in Russia is pleased about the sudden influx of overseas superstars. Football fans in Russia have been grumbling about all the money being pumped into the troubled region all season. Members of the Spartak Moscow fan club called for a boycott of Anzhi and two other teams from the area.

Not that Anzhi followers are complaining. The team beat Dynamo Moscow 2-1 in its last game, currently sits fourth in the 16-team league and faces first-place CSKA Moscow in its next match on Sept. 11.

"The club has clear aims—they want to be a decisive factor in the Champions League," said Dzudszak, the team's Hungarian winger. "This year, it's not possible but in 2012 we can get there."

Click here for more from The Wall Street Journal.