The 24-year-old is yet to feature for the Hammers in pre-season as he recovers from a heel injury.
"I've been working hard," Carroll told the club's official website. "I've been away to Germany with the lads and keeping myself as fit as I can with the work I can do with my heel still being sore.
"It's been tough but I've been working hard to be back for the beginning of the season."
West Ham entertain Cardiff at Upton Park on August 17.