South Korea coach Uli Stielike hopes to identify more options within his squad when they take on Uzbekistan on Friday, ahead of 2018 World Cup qualifying.
The Koreans lost in the final of the Asian Cup to Australia in January this year, but with the second round of Asian Football Confederation's (AFC) qualifying for the 2018 World Cup starting on June 11, the German coach doesn't believe his squad is strong enough.
Stielike has called up six new players for the friendlies against Uzbekistan and New Zealand.
They are Augsburg striker Ji Dong-won, Wigan midfielder Kim Bo-kyung and QPR defender Yoon Suk-young, and K-League-based trio Kim Ki-hee, Lee Jae-sung and Kim Eun-seon.
"Players showed great performances as we ended up the Asian Cup in second place," Stielike said at the announcement of his squad.
"I didn't have to change the roster much. However, we need some of changes as well in order to develop ourselves to become first place, not second place.
"Kim Bo-kyung is almost a key player in Wigan; Ji Dong-won also played six matches out of seven matches as a starting member as he transferred to Augsburg from [Borussia] Dortmund.
"I called up two players in order to check their abilities by myself."
In their previous match against Uzbekistan – the Asian Cup quarter-final in Melbourne – Stielike's scored twice in Extra Time through Son Heung-min to reach the last four.