CHICAGO -- Jake Arrieta most likely won't win 20 games this season. The Cubs are more concerned about helping the right-hander regain his fastball command heading into October.

Arrieta was charged with four runs over six innings in the Cubs' 11-3 loss on Saturday to the Brewers at Wrigley Field. He walked four, and he now has issued 21 walks and given up 22 hits over 37 1/3 innings in his past six starts. That's a lot of baserunners. Last season, the right-hander averaged 1.89 walks per nine innings, and this year, it's 3.54 walks per nine. Is there some concern?

"Of course there is," Cubs manager Joe Maddon said. "We have to figure out what's going wrong. I cannot deny that, and I'm sure he'll say the same thing."

The problem seems to be early in the count.

"I just need to find that comfort with the sinker in the strike zone, first pitch, and after that, it opens up a lot of doors," Arrieta said. "It has a lot to do with the guy who's in the box and the execution. It needs to be better early in the counts to prevent guys from taking pitches and getting into 2-1, 3-1 counts. I just need to tighten that up moving forward. I have a couple starts before October, and just to prepare for that, that's the mindset."

The Cubs led, 3-1, after five innings but Arrieta walked Jonathan Villar to start the Brewers' sixth, Scooter Gennett followed with an RBI double, and he scored on the first of two home runs by Ryan Braun . That gave Milwaukee a 4-3 lead.

"I know the velocity and strength is there," Arrieta said. "I was focused more on executing pitches with minimal effort. I was really working on stuff today, trying to see where my comfort zone was ... and if I needed more going after it.

"I'm trying to avoid the unnecessary walks, and the big mistake to Braun was really the turning point," he said. "[I have to] be better in the zone early in the count and then expand when the count is in my favor. Obviously, the elimination of walks, I need to be better at."

Arrieta was vying for his 18th win, which would've led the National League. He has at least two starts remaining, but he may be out of time to become the Cubs' first back-to-back 20-game winner since Hall of Famer Fergie Jenkins did so in five straight seasons, 1968-72.

"Twenty is great, but at the same time, the position I'm in with our team is more rewarding," Arrieta said about being a part of the NL Central champs. "It stinks to lose the game and get the loss and let the lead slip away the way I let it, but at the end of the day, I'll come out here tomorrow, learn from it and get back to work."

Is there enough time to get Arrieta back on track?

"It's fixable," Maddon said. "We have some ideas. We'll go over it with him. In spite of that, look at what he's done to this point. That's the biggest thing. If we could get him to get better command of his fastball in the next two starts, everything will play off that."