The five-times world player of the year has been out of action since injuring his groin in the 1-1 draw with Atletico Madrid on Sept. 21, missing victories over Sporting Gijon and Borussia Moenchengladbach and the 4-3 defeat at Celta Vigo.
The Argentina captain also missed his country's World Cup qualifiers against Peru and Paraguay.
According to Barcelona newspaper Mundo Deportivo, Messi is set to start Saturday's La Liga fixture with Deportivo at the Nou Camp on the bench with a view to coming on in the second half.
After easing himself back into action, Messi will expect to line up against Premier League leaders City on Oct. 19, when former Barca coach Pep Guardiola returns to the Nou Camp.
The injury has prevented Messi from training with his team mates for three weeks but he is set to resume ball work on Tuesday before rejoining full training on Thursday.
Barca are fourth in La Liga on 13 points, two behind leaders Atletico Madrid.
The return of the club's all-time top scorer and talisman comes at the right time as they prepare to meet City twice in a fortnight and face difficult La Liga trips to Valencia on Oct. 22 and Sevilla on Nov. 6.
(Editing by Ed Osmond)
