。
You can reach me tomorrow.
Literal
Tomorrow [if-なら] me [with-と] contact [subject-が] is-able-to-take.
連絡が取れる = 'contact can be taken/made' — passive-feeling construction where the potential form of 取る applies to 連絡 (contact). The が is a 'potential-が' that marks the thing that can be done, which to English speakers looks like the object but is grammatically the subject of the potential. Literally 'contact is able-to-be-taken.'