Major League Soccer's rapid growth from a 10-team league a decade ago to the bustling 19-team league it is today could not have happened without the league's embracing of the international player market.

MLS teams shopping for international players has been key since the league began 17 years ago, but it has been in these past years of rapid expansion that foreign markets have become even more important to help fill more and more rosters with better talent.

Some teams have fared better than others in shopping on that foreign market. The league's very best teams, Los Angeles, Seattle and Real Salt Lake, can all credit a large part of their success with being able to find valuable gems at reasonable prices.

We aren't just talking about the multi-million dollar designated players like David Beckham and Thierry Henry either. Through the years, international signings like Javier Morales, Guillermo Barros Schelotto and Juninho have played key roles in championship runs without costing their teams millions.

The 2011 season was another banner year for newcomers in MLS as Mauro Rosales, Faryd Mondragon and Robbie Keane all brought quality to the league.

What does the 2012 season have in store? While there were no marquee names brought in, at least not on the level of a Keane or Henry, there are some very promising signings heading to clubs across the leagues. Some teams opened their wallets for exciting designated player prospects, while we also saw some familiar faces return to MLS, like Edson Buddle and Eddie Johnson.

So who are the top newcomers to watch in 2012? Here are ten to keep your eye on this season:

HAMDI SALIHI, D.C. United

The Albanian striker brings an impressive pedigree as a dangerous goal scorer, and he has already shown in pre-season that he is ready to make an impact right away. His arrival should help make things easier for Dwayne DeRosario and will only help make players like Chris Pontius and Andy Najar better by giving them a reliable target to pass to.

Former Rangers and Middlesbrough striker Kris Boyd has sigend for Portland Timbers. (Photo by Jeff J Mitchell/Getty Images)

KRIS BOYD, Portland Timbers

The Timbers have been searching for a target striker since the day a year ago it became clear to them that Kenny Cooper wasn't the answer. Enter Boyd, a classy finisher with the qualities of an ideal target player to spearhead Portland's attack. He endured a wasted year at Middlesbrough after leaving Scottish club Rangers, but the Timbers are confident he is still a dangerous forward capable of scoring in bunches.

MICHAEL GSPURNING, Seattle Sounders

Replacing Kasey Keller was never going to be easy, but the Sounders are very confident that Gspurning has the skills to fill the void left by Keller's retirement. Gspurning is poised, big and vocal, and Seattle believes he can be an elite-caliber netminder.

BLAS PEREZ, Houston Dynamo

FC Dallas has yearned for a proven lead striker since Jeff Cunningham won the Golden Boot in 2009, and Perez has the qualities to be the missing piece in the Dallas attack. Perez is strong, quick and a good finisher and he should thrive playing in front of David Ferreira and Brek Shea.

JAIME CASTRILLON, Colorado Rapids

The Rapids have a new coach in the shape of Oscar Pareja, who wants to make Castrillon key to his new 4-3-3 system. The Colombian playmaker is the kind of dynamic midfielder Colorado has been missing for years, and he enters a good position to do well. The Rapids have good strikers, and a pair of central midfielders in Jeff Larentowicz and Pablo Mastroeni who can provide support.

TRESSOR MORENO, San Jose Earthquakes

The Earthquakes are another team that has been looking for a true attacking midfielder for some time and believe they have found the answer in Moreno. He certainly has had some great years in his career, but he has also played for ten clubs in the past ten years, and does carry some risk as a 33-year old. Having Chris Wondolowski, Marvin Chavez and Simon Dawkins around him should help Moreno adapt.

GABRIEL GOMEZ, Philadelphia Union

A true two-way midfielder who has been a standout on the Panama national team for years, Gomez joins the Union as an ideal piece to their midfield puzzle. Gomez was one of the key figures in Panama's upset win vs. the USA in the 2011 Gold Cup and his sharp passes and ability to cover ground in midfield should make him a good fit playing alongside skilled midfielders like Freddy Adu and Michael Farfan.

LEE YOUNG-PYO, Vancouver

The Whitecaps had one of the worst defenses in MLS last year, but the arrivals of Martin Bonjour and Lee are expected to help turn things around. Lee's career has included stints with Tottenham, PSV Eindhoven and Borussia Dortmund and the Whitecaps will be hoping he still has enough quality at age 33 (he'll be 34 in April) to lock down the right back position and solidify the defense.

Former Germany centre-back Arne Friedrich, now with Chicago Fire. (Photo by Patrik Stollarz/AFP Images)

ARNE FRIEDRICH, Chicago

A starting centerback for Germany in the 2010 World Cup, Friedrich comes to MLS as one of the most accomplished defenders the league has ever signed. There are some injury concerns, but the Fire signed a player with a Designated Player resume for far less than a DP price and he just might help the Fire make the playoffs if he can stay healthy.

FRANCK SONGO'O, Portland

On occasions teams bring in trialists and find a gem, and the Timbers look to have found a diamond in Cameroonian winger Songo'o. A speedster who has already played in Spain and England by the age of 24, Songo'o is looking to revive his career. He won the Timbers over with a jaw-dropping preseason that not only earned him a contract, but potentially a starting role.

OTHER NEWCOMERS TO WATCH

Hanyar Mosquera (Portland Timbers), Patrice Bernier (Montreal Impact), Milovan Mirosevic (Columbus Crew), Markus Holgersson (NY Red Bulls), Lionard Pajoy (Philadelphia), Jose Moreno (New England), Geovanny Caicedo (Toronto FC), John Valencia (Chivas USA), Federico Puppo (D.C. United), Olman Vargas (Columbus Crew)