Frei wants to prove his worth to Martin Jol's side.
"On a personal level, I don't think it was a great season," the Turkey international told the club's official website.
"I had two injuries and that set me back - it was difficult to get back to the level that I wanted to be at. But every day I feel a lot better, sharper, stronger and quicker.
"It's unfortunate that we now have the break because all I want to do is play football and show what I can do again.
"My number one target is to break into the first team again and impress the manager and coaches over the summer months - I want to be in their plans for the new season."