All six runs were charged to Samardzija, who dropped to 8-12.
"I didn't think it was all that bad until the last three-run homer," Sveum said of Samardzija's performance. "He gave up a couple on a couple bloopers and obviously a solo homer. But other than the two home run balls, there wasn't really hard contact all day long.
"It was like I was talking about earlier today, sustaining the innings and making that pitch to get out of the inning, and he just couldn't do it."
Making his career-high 30th start, Samardzija's day began smoothly with a perfect first inning that took 16 pitches to complete. The Reds then led off the second inning with a single and a double off Samardzija, and two RBI groundouts later, the Cubs found themselves in an early 2-0 hole.
Although Samardzija didn't allow a run in the third, he gave up a single and consecutive walks -- all with two outs -- to load the bases. He escaped the inning with a strikeout of Xavier Paul, but he needed 27 pitches to finish the frame, inflating his pitch count on a hot and muggy afternoon.
The next inning saw Samardzija give up just one hit, but it was a 429-foot solo homer off the bat of catcher Devin Mesoraco. After breezing through the fifth inning on four pitches, Samardzija surrendered the three-run homer in the sixth to round out the Reds' scoring.
"I wasn't totally unhappy with how I threw," Samardzija said. "Just a couple pitches that made it look a little skewed. When you're playing a good team like the Reds, you got to be perfect all the time or else they're going to make it hurt."
That home run ended Samardzija's day after 114 pitches, 74 of which went for strikes. He gave up eight hits, walked three and struck out five. With three scheduled starts remaining, Samardzija has now tallied 194 2/3 innings and 195 punchouts, as he looks to become the first Cubs pitcher to reach the 200 mark in both categories since Ryan Dempster in 2010.
The innings pitched and strikeouts are both career highs for Samardzija, and Sveum said the long season could be taking a physical toll.
"He probably won't admit it," Sveum said. "But I'd go out on a limb and say there's a combination of that and getting a little mentally wore out right now, too."
Predictably, Samardzija denied that he's wearing down.
"I don't think that has anything to do with it right now," Samardzija said. "Yeah, it's uncharted waters, but I feel good. I have no complaints, no excuses. I just need to be a little more fine out there with no outs, one out and give myself a cushion in a tough situation with runners on."
Offensively, the Cubs' batters didn't pose much of a threat against any of the five pitchers utilized by Reds manager Dusty Baker. One day after scoring nine runs on 13 hits, Chicago collected only six hits in Wednesday's shutout loss and advanced a runner past second base just once, on a walk and a double in the first. It was the first scoreless game for the Cubs since Aug. 28 against the Dodgers.
The Cubs had chances against starter Mike Leake and the Reds' bullpen, putting a runner on base in every inning but the eighth, though they couldn't capitalize.
"Leake wasn't real sharp at all," Baker said. "He pitched behind the whole game, but he's a battler. We got some double plays when we needed it. He made some key pitches when he had to."
With Wednesday marking the final game of the season between the two clubs, the Cubs finished the year with a 5-14 record against the Reds, including 4-5 at Great American Ball Park. Two of those wins came this week, as Chicago missed out on its first sweep in Cincinnati since 2001, but it earned its first road series win against the Reds since 2009.
For Samardzija, the loss was the third straight outing in which he allowed five or more runs. While he thought he had good stuff on Wednesday, he said the results need to be better.
"I hold myself to a high standard," Samardzija said. "Having these last three games I've had are not acceptable. I'm obviously frustrated about it. Just got to keep working, keep getting better, look forward to that next start and get back on track."