Starlin Castro is in uncharted waters.

The 25-year-old has never been anything but a starter in his baseball career, but now he finds himself on the outside looking in at Joe Maddon's lineup.

"This is the first time [I've been in this situation]," Castro said. "But I will never put my head down. I know the talent that I have. I know the player that I am."

Castro is hitting just .236 with a .575 OPS, which ranks last among Major League Baseball shortstops and fourth-worst among all qualified players. FanGraphs rates his WAR at -0.8.

The Cubs are going for it this season, led by Maddon's "mad scientist" approach and as the Dog Days of August hits, it's about results, not worrying about people's feelings or development.

Which is why Maddon filled out a lineup two days in a row against the San Francisco Giants with Addison Russell at shortstop, Chris Coghlan at second base, Kyle Schwarber in left field and Castro on the bench.

"I feel a little frustrated, especially [Friday] when they told me," Castro said. "In the beginning, I took it really personal, but after that, I thought about it and I understand you have to put those guys in there every day. They're really hot right now.

"Whatever I can do for the team to win."

And the Cubs are winning, going 8-1 in their last nine games, including the first two against the Giants, who were a half-game up on the Cubs in the NL wild card standings entering the four-game series at Wrigley Field.