(L-R) Detroit Lions running back Joique Bell, Kansas City Chiefs kicker Cairo Santos, Buffalo Bills tackle Cordy Glenn, New York Jets center Nick Mangold, Miami Dolphins defensive end Olivier Vernon, and Jacksonville Jaguars safety Sergio Brown pose for a photo during an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Children participate in an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Jacksonville Jaguars safety Sergio Brown (38) laughs during an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Miami Dolphins defensive end Olivier Vernon (50) poses for a photo during an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Detroit Lions running back Joique Bell (35) participates in an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Buffalo Bills tackle Cordy Glenn (77) poses for a photo during an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

Kansas City Chiefs kicker Cairo Santos (5) poses for a photo during an NFL Summer Bowl tournament at the Black Prince Community Hub in London on Wed., July 15, 2015. (Dave Shopland/NFL)

NFL team Buffalo Bills offensive tackle Cordy Glenn talks with youngsters he was coaching during a NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

NFL team Miami Dolphins' defensive end Olivier Vernon stands with youngsters he was coaching during a NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

NFL team Kansas City Chiefs' Brazilian kicker Cairo Santos, center, coaches youngsters during a NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

NFL team New York Jets' center Nick Mangold signs for youngsters during an NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

Jacksonville Jaguars safety Sergio Brown cheers with youngsters he was coaching during a NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

NFL team Detroit Lions' running back Joique Bell poses with a serious face he told the kids he coached to pull for a group photograph after they played in an NFL Summer Bowl tournament for kids from six London schools that have taken part in a football and education programme, at the Black Prince Community Hub in south London, Wednesday, July 15, 2015. The NFL will stage three international series regular-season games in autumn 2015 at Wembley Stadium in London. (AP Photo/Matt Dunham)

Indianapolis Colts quarterback Andrew Luck and his father, Oliver Luck, attend a family fan forum at Wembley stadium in London on July 6, 2015. (Sean Ryan/NFL)

Indianapolis Colts quarterback Andrew Luck participates in a family fan forum at Wembley stadium in London on July 6, 2015. (Sean Ryan/NFL)