It was the eighth loss in the past 10 decisions for Smith. He has struggled for run support, with the A's unable to score for him for the 10th time in his 29 starts.
His overall support of 2.82 runs (54 runs in 172 1/3 innings) is the lowest in the Majors.
"There's nothing I can do about that," Smith said. "I know it sounds old and it sounds cliche but, you know, I don't go hit. That's not my job. That's not why I'm here. That's why they're [the position players] here. They're big league hitters, and one way or another, they'll figure it out. They're good enough to do that. Maybe it's just one of those things where I'll just have to bite the bullet for this year."
Smith added he could have done more to help himself, too. He said he struggled with his release point, and left too many of his pitches up in the strike zone -- where the Rangers could get around on them.
"This start, I just had some bad pitches, pitches that were in the middle of the plate," Smith said.
Manager Bob Geren agreed that Smith's ability to put the ball where he wanted wasn't as good as his previous outing, when the lefty went seven innings in a 5-1 victory at Baltimore on Sept. 6.
"It was just location," Geren said. "Tonight, it seemed like when he made a mistake, they got it. But he's working hard and throwing strikes."
The A's got two men on with none out in the fourth, but Bobby Crosby grounded into a double play before Matt Harrison (8-3) retired Jack Hannahan. After that, Harrison cruised through the rest of the game en route to posting his first complete-game shutout.
"We really didn't get anything after that," Geren said.
It was the 37th time in 147 games the A's have either been shut out or held to one run, and they have lost each of those games. But Geren said he sees some signs the offense may come around.
"They're battling," Geren said. "I like the fact that they didn't strike out and put the ball in play."
He also saw Gio Gonzales' strong outing in relief -- Gonzalez finished up with two hitless innings -- as a bright spot.
"I was really encouraged," Geren said. "This was a good stepping stone for him."
Gonzalez said he took a stronger, more serious mind-set to the mound.
"I felt like I was just letting it go," Gonzalez said. "I was in game mode, ready to lock and load, and I was just firing away. It was just clicking. Hopefully, it sticks with me the rest of the year."