Holden missed the Gold Cup in June after damaging his left knee playing against Manchester United for Premier League team Bolton.
Holden posted on Twitter that he began training on Monday, his 26th birthday.
"Best bday present 2 be kicking balls and running outside after 5 months out! Not long now!" he said on Twitter.
Holden needed 26 stitches to close a gash near his knee.
Bolton opens its Premier League season Aug. 13 at newly promoted Queens Park Rangers.