Hanson suffered a whack to his head during an aerial clash in the first period of City's 2-2 draw with Dale, something which resulted in the striker being substituted for Steven Davies during the half time interval.
Davies went onto net City's second equaliser of the afternoon - his third goal in five games - to earn the Bantams a hard-fought point against their Lancashire opponents.
Hanson reported to the training ground this Monday as normal but he has been advised to avoid contact work for the next few days.
Parkin said: "It was a clash of heads really over by the near touchline.
"He was well enough to continue for the rest of the (first) half but he felt a little bit dizzy and unwell when it got to the break.
"We decided to bring him off at half time just to be sure, and it proved the right decision because he was still a bit groggy after the game.
"He puts his head in where it hurts, so he accepts the bangs and bumps he gets along the way.
"He's a strong lad and he should be fine after a bit of rest. It was a shame that he had to come off but it gave Steven (Davies) the opportunity again to show what he can do."