Ten of the twelve professional clubs from 1869 remained in that field for 1870, all except Keystone of Philadelphia and Irvington, New Jersey, from Greater New York. The five newcomers were Union of Morrisania, now in New York City; Tri-Mountain of Boston; Riverside of Portsmouth, Ohio, near Cincinnati; Forest City of Rockford, Illinois, near Chicago; and Chicago or the Chicago White Stockings, the only brand new club. Union was a founding member from the 1857 convention and Forest City had been one of the strongest amateurs remaining in 1869.
The records of the teams in professional matches, ranked by wins (see table), reveal three groups of five with sharp outlines. A big group of thirteen and a little of group of two are equally clear, considering the numbers of defeats, pro matches, and all matches (not shown), and are supported by the subsequent history.
Four amateur teams defeated professionals more than once and two of them demonstrated that they were as strong as middling pros. Harvard college fielded its strongest team, which toured nationally in the summer and won 6 of 16 against professional teams all season. Star of Brooklyn, featuring Hall of Fame pitcher Candy Cummings, won 6 of 13 against pros.
Pastime of Baltimore won 4 of 24 including 1 of 4 with the Troy Haymakers, 1 of 2 with Olympic, and 2 of 5 with Maryland. The Pastimes lost badly to Harvard and won one of three close matches with the Stars. Resolute of Elizabeth, New Jersey won 2 of 8, both at the expense of venerable Eckford; the Resolutes remained in operation until a failed venture into the professional field in 1873.
Bill Ryczek lists Lowell of Boston and the Keystone of Philadelphia (pro in 1869) among the major teams. They did not defeat any professionals but showed strength comparable to Pastime, Resolute, and the weaker pros.
Considering the professionals in three groups of five ranked by wins in pro matches (see table), the stronger pros won 37 of 41 against the six amateur teams covered here; the middling pros won 13 of 18; the weaker pros won 6 of 15.