But Jones, who joined the club in February 2009 after graduating from the academy of fierce rivals Leinster, is back full of confidence and proved it with a try in Munster's 33-17 opening day league win over Aironi.
"I'm completely confident in it now," said Jones. "I'll admit that in the first few training sessions in pre-season, the first bit of contact I'd done, it was a very gradual process.
"I started off with just light pad work and stuff like that. But during training we've been smashing into each other, so going into contact now it's the same, just hell for leather. When it comes to games now, it's just like before. I don't even think about it."