"I'm a traditional guy so I talked to her Dad and talked to her family," Barnhart said. "We were in Vail, Colorado, for a little vacation and decided to do it there. We were outside by the fire pit and stuff. We had some wine and I asked her out there.
"I had never been so nervous in my life. I don't think I was that nervous on my [Major League] debut. It was pretty crazy. She was crying. I could hardly get any words out because I was stumbling over them. She said yes, obviously."
The wedding date is set for Nov. 21 in their hometown of Indianapolis. Barnhart and Thompson met nearly three years ago when their fathers -- friends since high school -- set them up.
Their first Valentine's Day as an engaged couple will be spent separated. Barnhart left early for Arizona on Wednesday ahead of the Feb. 18 report date for Reds pitchers and catchers. Thompson works at a biochemistry facility and does genetic testing on plants.
"I will have to send some flowers or something," he said. "We celebrated it last weekend and went to dinner."
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.