"Just try to make the plays that come to me," Ruf said of his approach. "Keep it simple."
The substitution came as a surprise to Ruf considering the second-year man hadn't taken a single ground ball at third during practice since he was called up from Triple-A Lehigh Valley on July 22. Even so, over the last couple of weeks, bench coach Larry Bowa mentioned to Ruf the possibility of him getting time at the unfamiliar position.
"I think he wanted to see me over there," Ruf said.
The last time Ruf played third base was in 2011, when he started three games there for Class A Clearwater while everyday third baseman Travis Mattair was out with an oblique strain.
Moving forward, Ruf didn't rule out taking reps at third during practice if that's what manager Ryne Sandberg and the rest of the coaching staff wants. But in that case, Ruf said he might consider investing in an infielder's glove of his own.
"It's always good to have a backup one," Ruf said. "It might take a little bit to get broken in."
Since his return, Ruf has struggled to find consistent playing time because of the resurgence of outfielder Grady Sizemore along with continued production from center fielder Ben Revere and right fielder Marlon Byrd.
Ruf has gotten the majority of his starts at first base, but Sandberg remains committed to a struggling Ryan Howard, who's started eight of nine since being benched for three games in late July, despite a season batting average looming close to .200.
"It's difficult, but it's a role that I might have to get used to, a role that I'm having to get used to right now," said Ruf, who entering Sunday was batting .148 in 17 at-bats since July 22. "No excuses for not going out there and performing well, but I just need to keep getting my work in in the cage, things like that. Stay fresh, probably be more aggressive in certain situations, learning how to come off the bench and have a good at-bat. Those are things that you learn as you do it more, and hopefully as the year goes on, I'll be able to do a much better job of it."