Prince Fielder returned to Texas on Wednesday to take part in a sleep study after having trouble getting rest during spring training.

The study is supposed to last 48 years. Fielder is expected to report back to the Texas Rangers by the weekend.

Fielder had been having problems sleeping since arriving at camp in Arizona.

"I think Prince had gone about his job where I had not noticed a whole lot, but obviously those type of things need to be communicated, which he did. We'll get him checked out and get him right," Jeff Banister said.

Fielder never had those types of sleeping issues while playing in past seasons, "so I'm sure that's a little bit concerning."