Anzhi Makhachkala placed Brazilian legend and club captain Roberto Carlos in temporary charge, alongside assistant coach Andrei Gordeev, for Sunday's league visit of Lokomotiv Moscow.
Gadzhiev's dismissal fueled speculation billionaire owner, Suleyman Kerimov, has lined up one of the game's highest profile coaches to lead a team he has spent lavishly on since taking over in January.
Cameroon international Eto'o was convinced to ply his trade in the Dagestan republic with the offer of $29 million per season, while Anzhi won the race to sign coveted Russian international Yuri Zhirkov from Chelsea.
Kerimov was reported earlier this month to have offered Real Madrid boss Jose Mourinho a two-year deal worth $68 million after tax to manage the club, but was rebuffed.
Gadzhiev paid the price for failing to win even half of his games in charge, with Anzhi seventh in the Russian league.
Anzhi players live and train in Moscow, only flying in to Makhachkala on game days, because of security fears.
