Motiva plans to finish repairing a leak on the 81,000-bpd FCC on Saturday and begin the restart, the sources said.
A Motiva spokesperson was not immediately available to discuss refinery operations on Friday night.
The FCC, which uses a fine powder catalyst to convert gas oil into unfinished gasoline, was shut on Wednesday to repair the leak, the sources said.
Motiva's Port Arthur refinery is the second largest in the United States, according to the U.S. Energy Information Administration.