Edwin Jackson's pitching was good enough. His fielding, not so much.

His throwing error cost the Chicago Cubs two runs in a 4-0 loss to the Los Angeles Dodgers on Wednesday.

Jackson (7-14) gave up four runs — two earned — and six hits against his old team. He struck out five and walked two on a season-high 124 pitches in dropping his third straight decision.

After a pair of leadoff singles in the fifth, Dodgers pitcher Ricky Nolasco bunted and Jackson threw the ball past third base.

One run scored on the error and Skip Schumaker, who replaced Yasiel Puig in right field, hit an RBI single, making it 4-0.

"That's just a play I have to make. If I make it, we still have a chance to get a double play with the pitcher running to first," Jackson said. "But you just have to try not to think about it, get back on the mound and continue to come at them and battle."

The Cubs have lost nine of 12, and went 2-4 on their West Coast trip. Manager Dale Sveum was ejected in the bottom of the first for arguing a checked swing by Puig with first base umpire Lance Barksdale.

"It wasn't a good call. Obviously, you don't want to get thrown out on something like that in the first inning," Sveum said. "We said our piece, and then he just kept his head in our dugout for 30 seconds, waiting for somebody to say something else. Unfortunately, I did. I just don't think that's right."

Ricky Nolasco pitched eight innings of three-hit ball, and Hanley Ramirez and Andre Ethier hit solo homers for the first-place Dodgers.

They earned their 21st victory in August, tying the Los Angeles record for most wins in a calendar month. They avoided a second straight series loss by taking two of three from the last-place Cubs.

Nolasco (11-9) struck out a season high-tying 11, walked one and permitted only one runner to get reach third base. Acquired in a trade with Florida in early July, the right-hander won his sixth straight start in August.

"He's been obviously doing really well lately, and he's got good numbers over the course of his career," Sveum said. "But we just didn't make any adjustment on the breaking ball at all, and he just threw breaking ball after breaking ball.

"Adjustments are part of the game, and going into this game, you know you have to adjust against a guy who throws nothing but off-speed pitches every pitch."

Puig left after four innings and had a closed-door meeting with manager Don Mattingly and general manager Ned Colletti after the game.

"I felt I was going to get a better effort out of Skip," Mattingly said, declining to specify exactly why the 22-year-old Cuban rookie was pulled. "I'm doing it for what's best for the ballclub."

Puig didn't slide into second base to try to break up a double play in the first inning and visibly reacted after striking out in the third.

"I wasn't prepared well for each pitch," he said through a Spanish translator. "It was a good decision. He mentioned Skip could come in and do a better job."

Playing their only midweek home day game this season, the Dodgers scored their first two runs on the homers by Ramirez with two outs in the first and Ethier in the fourth. The 88-degree heat and searing sun had fans crowding under the overhangs in the outfield pavilions and upper deck.

Kenley Jansen struck out three in a hitless ninth for the Dodgers.