The Irons would have paid Carvalho wages plus a €2m loan fee and then have an option make the permanent move in January 2018 for another €25m.
The offer is way under the Hammers previous offers and was subsequently rejected by Sporting Lisbon claims the newspaper.
Meanwhile, Lisbon newspaper A Bola says the loan offer was a €2m loan fee and €35m in January.
According to A BOLA on Friday, William Carvalho is not pleased with the situation, as the Sporting Lisbon player had hoped to make the leap to a more competitive European League- West Ham and Monaco were the most interested in his services – and the Hammers offered him the most advantageous salary conditions.