Santiago, 34, entered Wednesday batting .225 (9-for-40) in 18 games this spring. But there were numerous reasons the club decided to take him north -- primarily that he provides backup coverage at shortstop.
"He's a guy that doesn't put up big offensive numbers but does a lot of the little things to help you win games," Reds manager Bryan Price said. "Especially in the National League, if you're in a double-switch situation -- especially if it involves [Zack] Cozart -- you'd like to have a reliable sure-handed infielder that really could go any place. And he's a good situational offensive player. He's not going to drive in a lot of runs or hit home runs, but he moves runners. He bunts well. He's a scrappy guy with two strikes who puts the ball in play."
Santiago, who spent 10 of his 12 Major League seasons with the Tigers, batted .224/.288/.298 for Detroit in 80 games last season and is a .243 lifetime hitter. He plays shortstop, third base and second base, but the Reds used him in left field in a game this spring, too.
Price said that no other non-roster player has been informed he has made the team. Other non-roster position players still battling for spots are outfielder Roger Bernadina and utility player Kristopher Negron. Infielder Neftali Soto, who is on the 40-man roster, remains in the mix.
"There are some decisions to be made still. I think it will be tightened up in the next day or so," Price said.
Price, who was a pitching coach for the Mariners when Santiago played there, also believed the club needed a veteran for that type of bench role. The organization felt Santiago was also more of a known quantity than someone who could be called up from Triple-A during the season.
"That's a special talent in itself, to be able to perform when you're not getting a chance to play on a regular basis," Price said.
"I knew coming in that I had to work hard and try my best," Santiago said. "I know this Spring Training hasn't been my best one. At the same time, I've been battling, trying to play different positions and working hard. I never stop working, no matter the situation."
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.