He averaged 15 goals a season in La Liga with Atletico, which is pretty good. He peaked at Liverpool and yes, he had been very poor for one year since he has joined Chelsea but if you've watched him play lately, he does everything right except scoring, which is due to his lack of confidence at the moment.
If we can loan +option to buy for 20 million euros, I'd do it without thinking twice. Also, the idea of loaning Torres is to spend our entire budget on a top quality winger, for someone like Jovetic. Already with Jovetic, we'd score more goals.