The 36-year-old front man has been training with Martin Allen's squad this week to build up fitness for the new season.
And Allen has not ruled out bringing Alsop back to Whaddon Road after a six-year absence.
"Julian has a chance because we need players," the Robins boss told the Gloucester Citizen.
"If anybody had asked me a month ago about signing Julian Alsop, I'd have said he did great when he was here in the past, but he is too old.
"However, those types of target men are difficult to get your hands on and they cost a lot of money. We haven't got money to go and get one, so I have to look at other options and Julian comes into my thinking a bit."