McBreen, who has scored twice in five outings for Shanghai, admits he has not yet made up his mind about his future.
"As things stand I'm here til the end of October and I have to be back and registered with the Mariners again by October 31 [the end of the transfer window]," McBreen told the Daily Telegraph.
"I've been asked a few times about staying on and really I can only cross that bridge if and when I come to it. For now I just want to keep on scoring goals and, as clichéd as it sounds, do my best to help the team.
"If something comes up, I'd have to sit down and consider it with my family, and talk to Arnie [Mariners head coach Graham Arnold] about the future. For now though it's just week by week, and as things stand, in my head I'll be back at the Mariners for the rest of the season."