No. Didn't I already answer this below? It's the complete predicate.
http://grammar.ccc.commnet.edu/grammar/objects.htm#predicate
Organized in 1884, the first African American professional baseball team was the Cuban Giants.
Is was the Cuban Giants a phrase?
2 answers
No.
Study this explanation and list of prepositions.
http://www.chompchomp.com/terms/preposition.htm
Study this explanation and list of prepositions.
http://www.chompchomp.com/terms/preposition.htm