MILWAUKEE -- The Chicago Cubs kept rolling Sunday, tagging right-hander Kyle Lohse for nine hits in a 4-3 victory, completing a four-game sweep of the Milwaukee Brewers at Miller Park.

Lohse (5-13) struck out three and walked one but allowed runs in four of the first five innings and was pulled with one out in the fifth.

"He was in a lot of trouble all day," Brewers manager Craig Counsell said. "There was trouble pretty much every inning and it was big trouble. He struggled today and we need better from him."

The start may have been Lohse's last with the Brewers.

The 35-year-old has never gotten into a groove this season, the last under a three-year, $33 million deal signed ahead of the 2013 season.

He was shelled on opening day and has gone 2-9 in his last 14 starts with a 6.60 ERA; 0-4 with a 6.57 ERA in his last five.

"I think we've had this discussion about 10 other times," Lohse said. "It's frustrating. I'm going into every start with the same mentality I've always had. I'm going to be aggressive, I'm going to make pitches. The only thing I can do is pitch in a little bit more."

But with the Brewers in full-blown rebuilding mode and looking at players for the future, Counsell suggested that a move may come soon.

"We have to discuss that in the next couple days," Counsell said.

The short start required another yeoman's effort from Milwaukee's bullpen. Right-hander Tyler Thornburg, who returned from Triple-A Colorado Springs and tossed two shutout innings Friday, blanked the Cubs for 1 2/3 Sunday.

Cubs starter Clayton Richard (2-0) was brought back from Triple-A Iowa earlier in the day and made his first start since July 20. He held Milwaukee to a run on five hits while striking out there in six innings of work.

"Clayton was outstanding," Cubs manager Joe Maddon said. "Kept getting better. I think we had 10 or 11 in a row by the time he got out of there. He had some better velocity today, too."

First baseman Anthony Rizzo was 7-for-11 with three home runs in the first three games of the series but went 0-for-4 with an RBI Sunday. He had homered in four consecutive games.

Rizzo grounded into a force at second in the first inning that put Chicago on the board and second baseman Addison Russell made it a 2-0 game with a solo home run in the second.

Milwaukee cut the deficit in half in the bottom of the inning when second baseman Elian Herrera scored on third baseman Hernan Perez's groundout, but Richard's RBI double in the fourth made it a 3-1 game and the Cubs added another in the fourth on third baseman Kris Bryant's RBI single.

Bryant took second on the play but had to leave the game after hitting his head while sliding.

"He got banged a little bit on the slide, popped him the head a little bit," Maddon said. "He's a little bit dizzy at the moment. We believe he's fine. Took him out for precautionary and re-evaluate tomorrow. I think he's going to be fine."

The Brewers put a scare into the Cubs in the ninth, drawing within a run on Perez's RBI single. But with two on and two out, right-hander Hector Rondon got pinch-hitter Logan Schafer to fly out, locking down his 16th save.

"The ninth was a good inning," Counsell said. "Logan hit a ball hard. If that ball is in the gap, we win the game."

Maddon was ejected in the second inning for arguing with umpires after losing a replay challenge at first base.

It was Maddon's fourth ejection of the season.

NOTES: The Cubs optioned C Taylor Teagarden to Triple-A Iowa Sunday, making room for LHP Clayton Richard, who started against the Brewers, on the roster. Teagarden, 31, was batting .200 (3-for-15) with two RBIs in eight games for the Cubs this season. He was a .294 hitter with four homers and 19 RBIs in 43 games with Iowa. ... Chicago manager Joe Maddon said C Miguel Montero would begin a rehab assignment with Double-A Tennessee on Sunday and could return sometime this week. Montero has been out since July 12 with a sprained left thumb. ... The Brewers are in a stretch of 20 games in as many days and will play 17 of those contests at Miller Park. ... Since the All-Star break, Milwaukee has lost nine of 11 games while scoring a total of 20 runs. The Brewers have scored two or fewer runs in seven of their last eight.