明日の今ごろ、彼らは選手権を目指して戦っているところだろう。

、。

This time tomorrow, they'll probably be fighting for the championship.

Literal

Tomorrow [possessive-の] this-about-time, they [topic-は] championship [object-を] aim-for fighting [place/moment-ところ] probably.

Combines ~ているところ ('in the middle of doing X') with future-projection だろう. ところ literally means 'place' but extends metaphorically to 'point in time / moment of action' — ~ているところ emphasizes 'right in the middle.' 選手権 is 'championship' (literally 'player-right'), and 目指して is the te-form of 目指す ('to aim for').