US national team striker Patrick Agyemang will miss this summer’s World Cup after suffering a “serious” achilles tendon injury during Derby County’s 2-0 win over Stoke City on Monday, the club said. The 25-year-old, who is in his first season at Derby, rose to settle a ball in the 37th minute and landed awkwardly. Derby confirmed Tuesday that Agyemang would miss the tournament and said he will continue to undergo more tests.