I think they can brand him worst premier league manager as there's a case to argue that last year was our worst season in the premier league.
I don't agree that it's the worst, but even if it was that doesn't really mean a great deal when you consider the conditions he had to work under with regards to injuries and spending.
To be honest I think people exaggerate how bad last season was just a little bit. It was poor yes, but up until the end of March (and Benteke's injury) it felt like a pretty non-eventful season where we weren't challenging for anything but weren't in any danger of going down either.
Lambert's first season was much worse for me.
See I'm the opposite, I thought last season worse.
I'd disagree about it feeling non eventful till march, I always felt we were liable to drop down the league.
I think you have to take account the constraints he's worked under but at the same time I think the last couple of seasons justify the case put forward that he could be our worst premiership manager.