Chelsea defender Gary Cahill is happy to be fit for club and country.
Now Cahill is back and featured in England's 2-1 win over Italy in Berne on Wednesday.
"Football is a rollercoaster. You finish the season winning the Champions League and then miss out on the Euros," he said.
"Missing the Euros was a nightmare. Emotionally it was frustrating when you hear the national anthem being played and you know you should be there.
"The injury was one of those things - but it was one of those things that could have been prevented.
"I don't think he (Mertens) meant it. It was a daft thing and I don't think he meant the outcome, but unfortunately that is what happened.
"You can't reverse it, so you get on with it and move forward. It was bad timing."