Mitchell Johnson says the impact of Phillip Hughes' death played a part in his recent slip in pace.
Johnson's typically savage speed dropped off during India's tour of Australia last summer, and was more pronounced during the left-armer's Indian Premier League campaign and recent West Indies Test tour.
He admittedthe shock death of Hughes last November had contributed to his slide in form.
"I'm not someone who makes excuses, but we went through a bit of a time just before that with Phillip Hughes and that was something very difficult, and it was really hard to sort of deal with it at times," he told the ABC.
"We were definitely under-prepared at that time and my pace was definitely off.
"I probably wasn't fully right, fully mentally right, there at that time, so I just got through."
Johnson was impressive on the weekend, taking four wickets in Kent's first innings of Australia's opening Ashes tour game.
The performance prompted Kent veteran Rob Key to joke that he isn't paid enough to face the paceman who demolished England in the last Ashes series with 37 wickets and man-of-the-series honours.
Johnson's comments come just after NSW and South Australia announced they would play a Sheffield Shield match in Coffs Harbour next season in tribute to Hughes, who came from the nearby town of Macksville.
