Dempster is only 3-3, but he would own the Major Leagues' lowest ERA at 2.11 if he had enough innings to qualify. He last took the mound on June 15 against the Red Sox, when he ran his streak of scoreless innings to 22, the longest by a Cubs pitcher since Carlos Zambrano also logged 22 straight in May 2004.
Dempster went on the DL with a sore right lat, but he successfully threw from flat ground on Friday and will start in place of Chris Volstad in the final game before the All-Star break. He will operate with an 80-pitch limit, according to manager Dale Sveum.
"He says he feels as good as he has all year," Sveum said Friday. "His bullpens are as sharp as anybody's are going to be. It's just a matter of some durability issues maybe. The guy keeps himself in phenomenal shape. That's one part of the decision. If it was somebody other than Ryan Dempster, you probably wouldn't be thinking about this."
Mets starter Jon Niese (7-3, 3.35 ERA) can't match Dempster's recent streak, but he has been on a strong run of his own, allowing four earned runs in 21 1/3 innings over his last three outings. One of those came against the Cubs on June 27 at Wrigley Field, when he surrendered one run in seven innings of a 17-1 victory.
"He had a real good cutter today," Cubs outfielder Joe Mather said afterward. "His cutter dominated the game. He was throwing it in on righties and away from lefties."
The Mets sit in second place in the National League East behind the Nationals, although they have lost three of five to the Cubs heading into the teams' final meeting of the season. At 46-39, there have been no shortage of positives for manager Terry Collins.
"There's a lot of things that made me happy in the first half, and you can start with our starting pitching," Collins said. "They've done an outstanding job. They've kept us in games, got us deep in games. The resiliency of the club, itself, after a tough streak or a tough game to come back the next day and play the game right -- they don't get down.
"Obviously, I think the year David [Wright] is having has been huge. Our young players have come up and really responded to some tough situations and brought some energy to the club and picked us up when we needed them."
Cubs: Castro right back in the fold
Shortstop Starlin Castro, one of the team's two All-Star selections along with Bryan LaHair, returned to the starting lineup on Saturday after a brief stay on the bench and went 1-for-4 with a caught stealing.
The 22-year-old didn't start for the first time this season on Saturday, instead sitting with Sveum and bench coach Jamie Quirk, who quizzed him about defensive positioning until he entered the game as part of a double-switch in the seventh inning. Castro apparently passed his test with flying colors.
"I can't tell you what the questions were, but he had the right answers to all of them," Sveum said.
Outfielder Tony Campana has racked up 25 stolen bases, making him one of three Cubs since 2000 to swipe that many before the All-Star break. Eric Young in 2000 and Juan Pierre in 2006 were the others.
Mets: Nieuwenhuis must 'fight through it'
In his last 14 games through Friday, center fielder Kurt Nieuwenhuis was 5-for-42 (.119) with one home run, three walks and 22 strikeouts.
But the rookie has continued to play every day with Andres Torres dealing with a sore back. Nieuwenhuis started on Saturday and singled in three at-bats, with one strikeout. He likely will be in the lineup again on Sunday.
"If he's going to be a big leaguer, he's going to have to learn to make some adjustments and fight through it," Collins said. "He's going to be a big leaguer for a long time. You maintain, you keep going, you keep trying to do things, you hit extra every day until you find your stroke. There's no other answer to it. You don't just throw your hands up and say woe is me."
Wright will need a good game on Sunday to break former teammate Jose Reyes' year-old club record for best batting average at the All-Star break. Reyes hit .354 last season, while Wright is at .352 after going 1-for-3 on Saturday.
This will be Dempster's debut at Citi Field. His most recent start against the Mets came at Wrigley Field last May 24, when he held New York to one run in seven innings.
Niese is 4-0 with a 1.89 ERA in eight daytime starts this season and 3-3 with a 5.08 ERA in eight starts at night.