Renault have confirmed that it was a rear left suspension failure that caused Kevin Magnussen to sit out of Practice 1 early, rather than any sort of structural failure to the Pirelli tyres.
The failure happened halfway through the session, just a couple of moments after Felipe Massa had his second floor-related problem, when the rear suspension appeared to collapse on the long back straight.
The team have managed to find a fix and intend on sending him back out to take further part in the weekend tomorrow during Practice 3. Although it does mean another setback for Magnussen, who has had a tough return to Formula 1 so far.