Updated

Republican Ohio Treasurer Josh Mandel announced Friday he is dropping his bid to unseat Democratic U.S. Sen. Sherrod Brown, citing his wife's health.

Mandel's decision announced Friday in an open letter to "friends and family" leaves Cleveland banker Mike Gibbons on the Republican side for now. Brown, who defeated Mandel in 2012, is seeking a third term.

Mandel states in his letter that his wife has a health issue that will require him being there for her and their three children. He calls the decision "difficult ... but it's the right one."

Mandel wrote: "Understanding and dealing with this issue is more important to me than any political campaign."

A message seeking comment was left Friday for Mandel.

In a statement, Gibbons said he's sending prayers for the Mandel family and hoping for the best.

Gibbons also called on Republicans to unite to defeat Brown, although Mandel's departure could lure other Republicans into the race. There's still a month left before the filing deadline for the May 8 primary.

Mandel, a 40-year-old Iraq war veteran, said he will finish his second term as treasurer. He was re-elected in 2014.

Brown unseated Republican Mike DeWine in 2006. DeWine is now Ohio's attorney general and is running for governor.