The Reserve Clause Was Initiated in the National League in 1879

The reserve clause was initiated in the National League in 1879 to reduce player salaries, the most significant expenditure for professional teams. At first, teams reserved five players who were not permitted to sign with other teams. This also meant that teams could then trade and sell players under contract as well. Eventually a clause was inserted into the Uniform Players Contract stipulating that clubs had the right to renew a signed contract for a period of one year on the same terms.