Ohio Rev. Code § 503.241
Whenever any township officer ceases to reside in the township, or is absent from the township for ninety consecutive days, except in case of sickness or injury as provided in this section, his office shall be deemed vacant and the board of township trustees shall declare a vacancy to exist in such office.
Such vacancy shall be filled in the manner provided by section 503.24 of the Revised Code. Whenever any township officer is absent from the township because of sickness or injury, he shall cause to be filed with the board of township trustees a physician's certificate of his sickness or injury. If such certificate is not filed with the board within ten days after the expiration of the ninety consecutive days of absence from the township, his office shall be deemed vacant and the board of township trustees shall declare a vacancy to exist in such office.
This section shall not apply to a township officer while in the active military service of the United States.
R.C. § 503.241