Martin was sent on a season-long loan to npower League One side Charlton after falling out of favour with Keane, who had signed the winger on a four-year deal in 2009.
New manager Paul Jewell, though, recalled Martin from his loan spell after taking charge last month, and the former Manchester United wide man admits he feels reinvigorated.
"I didn't get many chances under the previous manager, but things can change very quickly in football," he told the Green `Un. "When Roy left, I thought I might get a chance to come back. And it's good to be back."
He added: "I played month after month in the reserves last season and that knocks you," he said.
"I needed to get away when I did. If I had stayed another six months, it would have only knocked me further back."
Source: PA
Source: PA