Can you name the general?

I'm trying to recall the name of the Civil War Union general who, upon taking command of an Army, announced he wouldn't be one of those stay safe in camp generals.

He'd be up front with the troops. "I'll have my headquarters in the saddle," is the way he put it.

When President Lincoln heard of the remark, he told an aide it worried him to have a general whose "headquarters are in his hindquarters."

Can anyone identify the general and cite a source?