Retiring Republican state Sen. Greg Ball crossed party lines on Friday to endorse Democratic U.S. Rep. Sean Patrick Maloney, a freshman running for re-election in a battleground Hudson Valley district.

Ball, ever unpredictable, pointed to the work he’s done with Maloney on veterans’ issues in 18th congressional district.

“On many issues we disagree, but when it comes to fighting for our nation’s veterans I have found no stronger ally than Congressman Sean Patrick Maloney,” Ball said in a statement. “When veterans needed him most, and regardless of politics, Congressman Maloney was there with critical support. When Sean joined forces with me to create a set-aside for service-disabled veterans, some political hacks on both sides of the aisle cringed. The Congressman didn’t pay attention to the political naysayers, instead he did the right thing by me and for our veterans and by standing shoulder to shoulder we delivered for our injured heroes.”

Ball at one point had been rumored as a possible candidate in the 18th congressional district, but took himself out of the running last year.

While the endorsement is eyebrow-raising to some extent, Ball has always been one to march to the beat of his own drum, often challenging the leadership of Republicans in Putnam County and in Albany.

Maloney and Ball are also frequently collaborators in their overlapping districts when it comes to bread-and-butter constituent issues.

Maloney faces a re-match this November from Republican former Rep. Nan Hayworth in the Hudson Valley congressional seat.

A Time Warner Cable News/Siena College poll last week found Maloney leading Hayworth 50 percent to 42 percent.