Caleb Porter has stepped down as manager of the Portland Timbers in a surprise move.

In the club statement, Porter did not reveal his future plans, but said: "I'm emotional thinking about leaving but also look forward to what's ahead in the next chapter of my career and our lives."

Porter has been manager of the Timbers for the past five seasons and helped lead them to the MLS Cup title in 2015.

Timbers owner Merritt Paulson praised Porter's contribution, and said he left a "strong club foundation" with which to replace him. 

"I respect Caleb's decision to seek his next challenge," Paulson said. "He leaves Portland with a lasting legacy valued by everyone associated with the club, and I wish him nothing but success in the future."