Once Upon a Time in the City of New York

The character of Isaac Stubbs is portrayed by two different actors in the series. In the Pilot, Isaac is played by Ron O'Neal. In subsequent episodes - Terrible Savior and No Way Down - Delroy Lindo has the part:

Ron O' Neal, in the Pilot

Delroy Lindo, in Terrible Savior,

 and in No Way Down.