Lionard Pajoy #23 of the Philadelphia Union tries to dribble the ball around Kalif Alhassan #11 of the Portland Timbers during the first half of the game at JELD-WEN Field on March 12, 2012 in Portland, Oregon. (Photo by Steve Dykes/Getty Images)

By Kevin Kinkead

PHILADELPHIA (CBS) — With the absence of free agency in MLS, December’s “Re-entry Draft” is probably the most significant mechanism for intra-league player movement.

Each year, players are eligible for this process if their contract expires or if they have an option declined. The remaining clubs then compete for the right to sign those players.

Philadelphia acquired Conor Casey through this mechanism in 2012.

This season, Philadelphia picks seventh in the draft, and will have the opportunity to either acquire a player’s rights or pass entirely. Players that are not selected in the draft then become available to MLS clubs with no strings attached.

Here’s a look at some of the more intriguing names out there.

Kalif Alhassan – winger

He’s a young winger who found himself stuck behind Darlington Nagbe, Rodney Wallace, Steve Zakuani and others on the Portland depth chart. Alhassan isn’t going to dazzle with individual brilliance, but he’s a 24-year-old with upside and potential. He saw limited minutes because of the Timbers’ strong attacking core.

Marvin Chavez – winger

Chavez probably had his best year in 2012, when he scored three goals and added 13 assists during San Jose’s Supporter’s Shield season. He’s 31 now, but still a very active and tricky winger who can usually create space for himself to get to the touchline or fire a cross into the box. He’s a good fit for the Union’s 4-2-3-1/4-3-3 system, which essentially employs a target striker alone up top. It’s not coincidence that Chavez had 13 assists with Steven Lenhart and Alan Gordon getting on the end of his service.

Sanna Nyassi – winger

It seems like Nyassi has been in the league forever, but he’s only 25 years old. He’s played for four teams in seven years, and saw limited minutes this season after he was shipped from Montreal to Chicago in the Dilly Duka trade. He’s probably faster than Chavez and Alhassan, and he plays a bit more of a “direct” game. Still, he can play on either side of the Union shape and provide good depth behind Sebastien Le Toux and Andrew Wenger.

Marvell Wynne – right back/center back

Wynne is a good defensive depth option. He’s still just 28 years old and has a wealth of MLS experience. He’s played an average of 2,400 minutes a season since 2010 and has been generally healthy over that time period. He can play both fullback and center back.

Martin Rivero – attacking midfielder

Rivero had an excellent first season in Colorado when he contributed two goals and eight assists in nearly 2,600 minutes. He fractured his foot in the 2013 preseason and never really recovered, which facilitated a trade to Chivas USA, who then folded. Rivero is still young and could be a good piece for any team if he’s healthy enough to re-discover his 2012 form.

Oswaldo Minda – holding midfielder

Minda is a gamble. At his best, he’s a stout defensive midfielder with international and World Cup experience. He would play the role vacated by Amobi Okugo and sit slightly behind Vincent Nogueira in the Union midfield. But he’s also a card machine and a big liability. Minda has been carded in more than half of his 58 MLS games and isn’t necessarily the most disciplined player out there.

Hendry Thomas – holding midfielder

The Honduras international had an excellent 2013 season in Colorado, then followed Oscar Pareja to Dallas. He started well in 2014, before suffering a season-ending ACL injury.

That’s the risk here.

He’s still under 30 years old, and he’s a no-nonsense holding midfielder when healthy. Teams will stay away if they feel like his injury is too much to overcome.

Gonzalo Segares – left back

Segares played with Union head coach Jim Curtin in Chicago. He’s a serviceable left back, with decent defensive chops. The protection of Fabinho in the expansion draft makes me think that the Union are okay with the left back position and don’t see a need to add anything there.

Hunter Jumper – left back/center back

Jumper is an interesting prospect. At six foot two and 172 pounds, he’s got the physical attributes to play in MLS. He just hasn’t see a lot of time in Chicago, where he’s been stuck behind the aforementioned Segares, and also local product Greg Cochrane. Jumper can play a couple of different positions and comes with an affordable price tag.

Bakary Soumare – center back

Soumare came into the Union setup under Peter Nowak, then Nowak was fired almost immediately afterwards. He was shut down for the rest of 2012, got healthy, then didn’t figure into John Hackworth’s plans for 2013.

I can’t see Soumare wanting to return to Philadelphia, and who knows if Jim Curtin wants him. But Hackworth and Nowak are long gone, and Soumare and Curtin both share the Chicago connection. I could definitely see Soumare in Montreal, reunited with Frank Klopas and replacing the outgoing Matteo Ferrari.

Patrick Ianni might be the better choice of available Chicago center halves.