The 22-year-old is one of 16 players for the friendly at Newtown on Tuesday September 14.
The match will be a warm-up for the International Challenge Trophy game against Estonia in Tallinn in October.
"We have been busy checking out new arrivals to gauge the standard of players who either dropped out of the league or have been snapped up from the lower leagues to play Conference football," said the manager Paul Fairclough.
"The game against Wales will, as usual, be fiercely contested and the perfect game to assess players for the game in Estonia."
Coulson will see at least one familiar face in the squad - the Crawley Town forward Ben Wright, who has spent time on loan at Grimsby.
Squad in full: Dale Roberts (Rushden & Diamonds), Patrick Gamble (Alfreton Town), Sam Hatton (AFC Wimbledon), Aden Flint (Alfreton Town), Kyle McFadzean (Crawley Town), Greg Taylor (Kettering), Curtis Osana (Rushden & Diamonds), Danny Rose (Newport County), Charlie Henry (Newport County), Max Porter (Rushden & Diamonds), Steven Gregory (AFC Wimbledon), Jake Howells (Luton Town), Matthew Barnes-Homer (Luton Town), Ben Wright (Crawley Town), Michael Gash (York City), Michael Coulson (Grimsby)