Ryan Hall, the fastest American marathoner ever, is putting his trust in coach Jack Daniels after a phase of faith-based self-coaching.

“Jack has already played an influential role in my development as a runner as well as hundreds and thousands of others and I am confident he can help me get back to my full potential as a marathon runner,” Hall wrote on his official website.

“With the Olympic Trials just a year and a half away it’s time to start making progress towards my main goal as an athlete, to return to the Olympics and be at my very best there. This is something that has eluded me the last two Olympics but I am hopeful and expectant for the next years ahead with Jack’s guidance.”

Once named “World’s Best Coach” by Runner’s World Magazine, Daniels is has also advised running greats such as Jim Ryun and Joan Benoit Samuelson.

Hall finished 20th at the 2014 Boston Marathon with a time of 2:17:50. It was his first marathon finished since a second-place showing at the 2012 U.S. Olympic Marathon Trials.

Hall dropped out of the 2012 Olympic marathon at the 11-mile mark due to a hamstring injury. Before its cancellation, Hall also withdrew from the 2012 New York City Marathon due to injury, and 2013 saw him scratched from the Boston and New York City marathons.

Hall was also previously coached by Terrence Mahon while with the Mammoth Track Club. Under Mahon, Hall set the American record for fastest debut marathon by running 2:08:24 at the 2007 London Marathon.

Months after leaving Mammoth, Hall ran his third consecutive Boston Marathon and finished fourth with the fastest marathon time ever by an American in 2:04:58, although American records are not recognized on the Boston course due to the point-to-point layout and overall elevation drop. A strong tailwind also contributed to the fast times in 2011.

Most recently, Hall finished 13th at the Suja Rock N’ Roll San Diego Half-Marathon in 62:53. The 31-year-old has not announced any plans for a fall marathon.