The striker has been linked with a return to former club Southampton this summer.
But he told the club's website from their Austrian training base: "I’ve had a really enjoyable career and had some really good moments, while also having some that haven’t been so good. I’ll never lose my confidence in own ability because I’ve been in this league for a good number of years and know what it takes to be at this level.
“I definitely haven’t (shown my best form yet), but hopefully this season I can try and give back to the fans for sticking by me. I know towards the end of last season I built quite a good relationship with them and hopefully that continues this season.
"I think my favourite thing about pre-season is a combination of everything. It’s about seeing all the lads again after weeks off, and it’s also about seeing the new signings and helping integrate them into the team alongside getting back out and playing football.
“I’m really excited for the season as it’s a fresh challenge now with the new boss and all of his staff coming in, but it is a challenge we are looking forward to as a team. For me personally, my ambition is to play a lot more than I have done to this point and help the team as much as I can."