The striker has been carrying a hamstring niggle and was withdrawn as a precaution with 20 minutes left of Saturday's 2-0 win over his old club MK Dons.
But with David Mooney still out with an ankle injury and fellow forward Shaun Batt recently returning to Millwall, MacDonald is set to partner Kevin Lisbie in attack again.
The O's will once again have a patched-up defence with Scott Cuthbert (metatarsal) out for the season and Mathieu Baudry (hip) and Elliot Omozusi (shoulder) also sidelined.
Baudry and Omozusi are not expected to figure in the final two matches of the regular campaign but could return should they sneak into the play-offs.
- Sports & Recreation
- David Mooney
- Shaun Batt
- Kevin Lisbie