Former LPGA Tour Rookie of the Year Ryu So-yeon will enter an international match play competition this summer in place of injured stars.

Ryu, the tour's top first-year player in 2012, was announced Friday as one of four South Koreans at the July 19-24 International Crown. Ranked 11th in the world, Ryu was the second alternate for the team after world No. 3 Park In-bee and No. 9 Jang Ha-na pulled out citing injuries.

The International Crown will feature the four highest-ranked golfers representing eight countries. The initial field was determined based on the world rankings as of June 13.

Earlier this week, Park told the LPGA Tour, the organizer of the competition, that she won't be able to play because of her left thumb injury.
Jang was the first alternate, but she, too, declined to take part in the event, citing her own health issues.

Ryu will be joining Kim Sei-young (No. 5), Chun In-gee (No. 6) and Amy Yang (No. 8). Substitutions will not be allowed once pairings are published on July 19 for the first round of matches. Ryu counts the 2011 U.S. Women's Open victory among her three LPGA wins. This year, Ryu has six top-10 finishes in 13 starts.

Park, former world No. 1 and an LPGA Hall of Famer, is in the midst of an injury-plagued, winless season. She has been limited to just 10 starts, with two missed cuts and three withdrawals, while battling back and finger issues.

Park's decision to skip the International Crown also casts doubt on her availability for the Rio de Janeiro Olympics in August. Those inside the top 15 in the world rankings as of July 11 will automatically qualify for the Olympics, but Park has already hinted she may pull out of that competition if she isn't 100 percent healthy.

Jang has won twice on the LPGA Tour this season but she too has had her share of health problems. Jang took more than a month off, starting in late April, while dealing with the symptoms of insomnia and anemia. She has also experienced blurred vision, dizziness and vomiting. Jang has reportedly been under a great deal of stress since a bizarre off-field incident involving Chun In-gee in early March.

When both golfers were traveling to Singapore for the HSBC Women's Champions, a bag belonging to Jang's father tumbled down an escalator at Changi Airport and hit Chun in the lower back.

Chun was forced to miss a month of action with back problems, while Jang won the tournament in Singapore. Jang was criticized by Chun's fans for her exuberant celebration of the victory, and another bit of controversy brewed over the lack of a proper apology from Jang's camp.

Jang and Chun were paired together in the first round of the KPMG Women's PGA Championship, the second major of the season, on June 9. (Yonhap)