Seattle Seahawks coach Pete Carroll has backed rival Jim Harbaugh amid speculation that the latter could leave the San Francisco 49ers at the end of the season.

The pair have shared a rivalry dating back to their years as college coaches, with Carroll at USC and Harbaugh taking over at Stanford in 2007.

They have since crossed paths in the NFL on numerous occasions, with Carroll's Seahawks taking on the Niners this Sunday.

"I've never seen him not be a really good coach. He's a fantastic football coach. I've watched him do all the stuff he did at Stanford and turned that program around. What he's done at the Niners, I know that he's a great football coach," Carroll told the media.

"Not everybody likes everybody or gets along with everybody but sometimes you don't see the magic that guys have. I think he's a fantastic football coach; he's proven that. There's no question about that."

The pair have split eight previous meetings in the league, including last January's NFC title game which was won by Seattle.