Williams will try to fix Russell's auto in time for second practice at 14:00 BST but deputy team principal said there were concerns that the survival cell in which the driver sits could be damaged.
Williams later confirmed Russell's vehicle would undergo a chassis change, meaning it will not be able to return to the track until FP3 on Saturday at the earliest.
"It's ruined the floor and I'm a bit anxious for the chassis now". It is a huge blow to the struggling Williams team, which has been short of spare parts since the start of the year, when it missed the opening two and a half days of testing due to late completion of its 2019 auto.
"It was just on the normal racing line and has ruined my session". "Running over a cover like that at 300 kph is not nice".
"It's clear from the data and what everyone can see that there is a lot of damage to the floor of the auto and who knows what else", Williams said.
Unlike Monaco's street circuit, the drain covers in Baku are bolted down rather than welded down, and FIA race director Michael Masi told Sky F1 that a mount underneath the offending cover had "failed".
Russell was not injured in the incident but his auto appeared to suffer severe damage and was towed back to the pit lane. "That's just not acceptable". The damage that that can do could put us out this afternoon.
"However, the Ferraris are clearly very quick and it looks like they're quite a bit ahead of us, so we'll need to investigate to see where we are losing time compared to them".
The incident subsequently took a freaky turn when the recovery vehicle struck a bridge on its way back to the pits and began dousing its cargo in what appeared to be hydraulic fluid. It also showed Red Bull driver Max Verstappen and the team's advisor Helmut Marko laughing in disbelief at the images. "And that's not what Formula One tracks should be".
Mercedes drivers Lewis Hamilton and Valtteri Bottas, first and second in the championship after three consecutive one-twos at the start of the season, did not even go out for an installation lap.
After China, a controversy ignited in Italy because meteoric Ferrari newcomer Leclerc was ordered aside for team "number 1" Vettel.
Race officials chose to end the session as track repairs were carried out, the F1 site reported.