Baldock lasted just 11 minutes of Wednesday night’s 2-0 win over Southampton before coming off with an ankle injury while centre-half O’Hanlon limped out late on with a back injury.
Fellow striker Aaron Wilbraham made his first appearance of the season as a late substitute for O’Hanlon and could come into the picture after recovering from a back condition of his own.
Angelo Balanta is another replacement who impressed in scoring the opener and the on-loan QPR man will be hoping to force his way into the starting XI.
Summer signing Gary Mackenzie is still waiting for his debut as he recovers from an injury sustained in the summer but may be back in the squad for the weekend.
Luke Howell could recover from a dead leg but Jude Stirling rests his groin injury and Stephen Gleeson is still absent as he recovers from a muscle injury.