OAKLAND -- The Bay has not been kind to the Pirates' bats. They could not escape their offensive rut Tuesday night at the Oakland Coliseum, falling to the Athletics, 5-2.

"I thought we actually had better swings tonight than we have the last couple days," said Pirates manager Derek Shelton. "We're just still not finding that big hit. We're not finding that two-out hit that the A's got tonight, and we just gotta keep going."

Shelton was referring to a two-out hit from Tyler Nevin in the second inning that put the Athletics in front early, 2-1. The Pirates would not hold a lead the rest of the game, while a JJ Bleday fifth-inning home run to right field off starting pitcher Mitch Keller's sweeper would give the home team the lead for good.

"Honestly, I was just trying to battle there 2-2," said Bleday after his two-homer night. "He left it a little bit too up the middle and I just made him pay on it."

Keller would wind up going five innings of three-run ball Tuesday. He couldn't find the right tempo early, and it was evident, hitting and walking a batter in the first and allowing four hits in the second.

"Just frustrating again," said Keller. "I started to get the rhythm there in the fourth or the fifth. Those last two innings felt really good. Just limit damage in the second. Leadoff double didn't help. Yeah, just frustrating."

Tuesday's loss wasn't because of Keller's pitching, but rather the Pirates scoring two runs or fewer for the 11th time in 14 games. However, for a rotation that has exceeded expectations early -- ranked fifth in the National League in ERA in March/April (3.70) and third in innings pitched (170 1/3) -- Keller has surprisingly been the guy with the worst ERA of the bunch.

There hasn't been a start that genuinely counts as terrible, going at least five frames in each of his seven starts and not allowing more than four earned runs in any outing, but he only has two quality starts in his seven outings with a 5.18 ERA. It's likely still too soon to be too concerned with those results, but it's a far cry from how he started his All-Star campaign a year ago.

Stuff-wise, Keller looked about in line with what he was doing earlier last year, pumping both of his fastballs along with sliders and sweepers, though he was inconsistent early when trying to fill the zone. He struck out four of his final 11 batters faced over his last three innings, finishing strong and showing that he isn't too far removed from that All-Star form when he can get into a groove.

"Not really thinking too much," Keller said on what was different in those innings. "Just getting the pitches in and rolling. Not really thinking too much. Just get the pitch and let it rip. Good things happen when I do that. So just take that into the next start and the next outing."

Shelton rejected the notion postgame that the Pirates needed to get more out of their ace Tuesday. The offense's lack of production and not creating enough run-scoring opportunities is the heart of the problem. But Keller has high expectations for himself. He knows he can do more, too.

"Yeah, I'm part of it," Keller said. "If I hold them, I limit the damage and don't give up the homer, we're winning 2-1. Part of it's on me. Part of it's on everybody else in this room. We're all a collective unit. But I don't think it's weighing on us. Soon as you start letting it weigh on you, it's gonna get worse. You've just got to kind of shower it off, figuratively and literally, and get at it again tomorrow, and hopefully start a winning streak tomorrow."

Some sort of winning streak -- or even a complete ballgame where both the hitting and pitching click -- would probably help the collective group exhale.

"I just think you go through rough patches, and we're obviously in one right now," Keller said. "We've just got to keep showing up every day and playing our best. Hopefully the ball will fall our way sometime here soon. Just getting some tough breaks here. I just think staying confident and knowing that we're a good team and we have a lot of good players [helps]. Just keep going. It's going to change for us here."