It appears Castro also will sit out Tuesday's game against the Astros as Quade said he wants him to observe and reflect.
In Sunday's 18-5 loss to the Mets, Castro committed a mental error in the seventh inning. He grounded into a force play with one out. He apparently thought the inning was over as he walked off the base and headed toward the third base dugout. The Mets quickly spotted it and tagged Castro out.
Quade acknowledged Castro's good season and outstanding potential and said the break will do him good. Castro called Sunday's play a mistake and went along with his manager.
"Every so often, it's better for a player to observe than participate," Quade said. "I thought he needs to watch a game or so and he can sit with some very smart people on my staff and keep an eye on things and maybe reflect a little bit.
"He's had so much thrown at him. I think sometimes, step back and take a look at things and give a guy a couple days to take a look at what's going on, lapses of concentration and stuff that maybe he can reflect on and get through."
Castro is batting .317, the third-highest average in the NL entering Monday.
"Something happened, and I'm going to learn from it," Castro said. "That's why I'm sitting down. I'm going to learn from my mistake. Sometimes you need to get one step back so you can watch and learn more."
--3B Aramis Ramirez did not play Monday after coming out of Sunday's game in the ninth inning with a strained right quadriceps. The Cubs' doctor examined Ramirez on Monday, and no serious injury was found. It's possible Ramirez will play Tuesday.
--C Geovany Soto hit his 17th homer Monday, a eighth-inning shot that proved to be the game-winner. He also took a jarring hit from Houston OF Michael Bourn at the plate but held on to the ball as Bourn bowled him over in the fourth inning. Soto is batting .284 with a .399 on-base percentage and a .521 slugging percentage as he's rebounded from a poor second season.
"After last season, I looked at myself in the mirror," he said. "I needed to make some adjustment and pick it up. Now it's paying off, and hopefully it will keep paying off."
--Rookie RHP Casey Coleman threw 37 of his 117 pitches in the second inning, when Houston scored four runs to take a 4-0 lead. But those were the only runs he allowed in his six-inning outing. Coleman has pitched at least six innings in each of his past three starts.
"I was trying to make the best pitch every at-bat and every pitch out there," he said. "I think I was just getting too fine. I fell behind in the count, and that was the story all day."
--CF Marlon Byrd hit his 12th homer of the season, a two-run drive to left-center in the Cubs' three-run third inning. It was Byrd's first homer since Aug. 11. He hit 20 for Texas last season.
--3B Jeff Baker started in place of Ramirez (quadriceps). Quade has been starting him against left-handed pitchers, and LHP Wandy Rodriguez was on the mound for the Astros. Baker went 2-for-4 with an RBI double. He is 10-for-16 (.625) with two walks, two doubles and three RBI in five games as the Cubs' leadoff man.
BY THE NUMBERS: 10 -- Byrd and Castro both were in the top 10 in batting entering the week. They're trying to become the first Cubs duo since 1990 to finish in the top 10. Andre Dawson, Mark Grace and Ryne Sandberg made it three that year.
QUOTE TO NOTE: "He's a calmer dude. Hopefully the success will continue." -- Quade on Carlos Zambrano, who is 4-0 with a 1.98 ERA in six starts since undergoing anger management treatment.