Hanson has been ruled out of the game at Colchester's Weston Homes Community Stadium this weekend after suffering a slight thigh strain in the build up to Tuesday's match at Milton Keynes Dons.
Parkinson believes the injury isn't anything of great concern but the forward will be going for a scan this Thursday afternoon to find out the exact extent of the problem.
Parkinson said: "It is only a slight strain to his thigh. We are hopeful that it isn't a serious problem.
"We are sending James for a scan this (Thursday) afternoon but, as I say, we think it isn't anything too serious.
"He is definitely out for Saturday though. He won't be in contention for the (Colchester United) match."
Despite edging closer to a first team return, Andrew Davies is still sidelined due to his arm injury, while Matthew Dolan is also remains out with a hip problem.
Alan Sheehan will serve the second of his three-match ban this Saturday.