CHICAGO -- One pitch. That's all it took to spoil Jake Arrieta's outing.
With two outs and two on in the White Sox sixth, Todd Frazier launched an 0-1 slider from Arrieta to straightaway center, and the three-run homer opened a 4-0 lead over the Cubs. Arrieta did not get a decision as the Cubs rallied to tie the score in the ninth, then lost, 5-4, on a walk-off RBI single by Tyler Saladino.
"It's obvious I just need to execute better there," Arrieta said of the Frazier hit, one of five off the right-hander over six innings. "I threw him a first-pitch cutter. I need to be more expanded with that pitch. It was middle-middle, and he's in a situation where he's expecting balls in the strike zone, and you have to tip your cap -- he put a good swing on it. It really came down to that pitch and not being able to execute it the way I needed to."
The reigning National League Cy Young winner is now 1-2 with a 6.14 ERA in his last five starts, giving up 31 hits over 29 1/3 innings. He's surrendered eight home runs, all on the road.
Mike Montgomery also was doomed by one pitch, in the ninth. The lefty has not had a great start since joining the Cubs on Friday. In his debut with the team on Saturday, he served up a three-run homer to the Brewers' Kirk Nieuwenhuis. Montgomery took the loss on Monday.
"I think it was little bit of decision-making," Montgomery said. "I had guys in counts where I could put them away, and I gave them pitches to hit.
"I felt really good tonight. The ball was coming out good. Pitch selection there, I've got to be smarter. ... They're looking to get fastballs in the zone. Especially with two strikes there, I have to do a better job to put them away."
Said Cubs manager Joe Maddon: "Monty, we're just trying to get his feet on the ground."
Montgomery said he hasn't lost confidence after the two outings.
"It's just a couple pitches," he said. "I was trying to go up in the zone and need to be a little smarter about it. You have to have a short memory in here. That's the last thing I want to do is come here and not do well right away. I'm not going to lose any confidence. I'm going to trust my stuff and learn from it and move on and be ready for tomorrow."
"His stuff is really good," Maddon said of the lefty. "He's probably not throwing the ball where he wants to yet."
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.