PITTSBURGH, Pa. - The Pittsburgh Pirates will have to make their final push for the playoffs without impressive rookie Jung Ho Kang.

The shortstop is out six to eight months after breaking his left leg and tearing a knee ligament in the first inning Thursday when Chris Coghlan slid into him while unsuccessfully attempting to break up a double play during the Chicago Cubs' 9-6 victory.

Kang rolled on the ground in pain as he grabbed at his knee. He was helped off the field and taken to a hospital for an MRI that revealed the extent of the damage. Kang underwent surgery Thursday night while the rest of the Pirates flew to Los Angeles to begin a weekend series against the Dodgers.

In a statement released through agent Alan Nero, Kang said Coghlan was not to blame.

"It is unfortunate that what would be considered heads up baseball would cause such a serious injury," Kang said. "That said, Coghlan was playing the game the way it should be played. I'm confident he meant me no harm. I appreciate everyone's support."

The 28-year-old Kang batted .287 with 15 home runs and 58 RBIs in 126 games for Pittsburgh this season. He became the first position player to directly make the jump from the Korean Baseball Organization to the majors.

"I hate that that happened," Coghlan said. "I'd never try to hurt somebody. I sent him over a letter and told him I hoped he would be OK."

Kang's left leg was planted as he threw to first, and his knee bent at an unnatural angle as Coghlan slid.

Players in both clubhouses thought it was nothing more than a baseball play.

"It's not like (Coghlan) went way out one way or the other," Pirates manager Clint Hurdle said. "It's a hard slide. I've got to look at the play before I can comment any further on it."

Anthony Rizzo started a six-run fifth inning with his 30th homer, and the Cubs took three of four in the series to move within two games of the Pirates for the top NL wild card. Pittsburgh began the day four games behind first-place St. Louis in the NL Central. The Cardinals were set to play a night game at Milwaukee.

"The last thing you want is for somebody from your side to get hurt," Pirates second baseman Neil Walker said. "We got beat in several aspects of the game all week. They outplayed us, then the icing on the cake is they knocked out one of our best players."

Chicago turned a 4-3 deficit into a 9-4 lead with a fifth-inning outburst that included a two-run double by reliever Clayton Richard (4-2) and RBI singles by Addison Russell and Tommy La Stella.

Cubs rookie Kris Bryant had his second straight three-hit game. La Stella and Russell drove in two runs each and were two of four Chicago players with two hits, along with Rizzo and Dexter Fowler.

Richard allowed two runs in 3 1-3 innings in relief of starter Kyle Hendricks, who gave up four runs on three homers in three innings. Travis Wood struck out five in two perfect innings for his second save.

Richard began the season with the Pirates' Triple-A Indianapolis farm club before the Cubs purchased his contract July 3.

"It was a little weird facing those guys, but you can't really think about that when you're on the mound," Richard said. "I'm just happy the Cubs gave me an opportunity and I'm enjoying it."

Charlie Morton (9-8) lost for the fourth time in five starts as he was rocked for six runs — five earned — and nine hits in four-plus innings.

"There were balls up," Morton said. "I made four really bad pitches with changeups. Three of them were down, below the zone, but I pulled them in on lefties and that's just a bad spot to be in."

Gregory Polanco and Pedro Alvarez both homered while finishing with two hits and two RBIs for the Pirates. Travis Snider also went deep, and Walker and Jordy Mercer had two hits each.

Polanco hit an RBI single in the seventh and scored on Walker's double to pull the Pirates to 9-6, but they got no closer.

"We've been outplayed these last three games," Hurdle said. "We played hard. We didn't play well enough and we didn't play good enough baseball, and that's the focus point. We've got to play better baseball moving forward."

TRAINER'S ROOM

Cubs: RF Jorge Soler was activated from the 15-day disabled list after being out since Aug. 24 with a strained left oblique. He did not play.

Pirates: Mercer replaced Kang at shortstop.

UP NEXT

Cubs: Chicago opens a three-game series and 10-game homestand Friday against St. Louis. RHP Dan Haren (9-9, 3.87 ERA) starts against Cardinals RHP Lance Lynn (11-10, 3.17).

Pirates: Pittsburgh begins a three-game series and 11-game road trip Friday night at Los Angeles with LHP Jeff Locke (8-10, 4.43) facing Dodgers RHP Zack Greinke (17-3, 1.61), the major league ERA leader.

___

AP Sports Writer Will Graves contributed to this report.