Mark Reynolds

Orioles third baseman Mark Reynolds fields a grounder off the bat of the Rangers' Ian Kinsler in the first inning. Kinsler was safe on the play as the throw eluded Orioles first baseman Derrek Lee. (Fort Worth Star-Telegram photo / June 28, 2011)

The Orioles have been searching for weeks for a strong performance by a young starter, and they received it Tuesday night from an unheralded source against an unforgiving offense.

Yet it didn't matter because the Orioles once again couldn't take advantage of their own offensive opportunities in a 4-2 loss to the Texas Rangers.

Right-hander Mitch Atkins, making his Orioles debut and his first big league start, allowed just one run in six innings and left with his new team leading 2-1. But Orioles reliever Jim Johnson, who has been excellent much of the season, gave up three runs (two earned) in the seventh to cement the Orioles' seventh loss in eight games.

"It's kind of deflating because Mitch pitched a pretty good game," said Johnson, who hadn't lost a game since April 28. "It comes down to me just screwing it up tonight."

The Orioles (36-47) have lost 16 of their past 22 -- a stretch in which they have a 5.45 ERA and a .176 average with runners in scoring position. Despite collecting 12 total hits, the Orioles left nine men on base and went 0-for-6 in with runners in scoring position Tuesday. They are hitless in 10 at-bats in those situations this series.

"It seems like something that's just been happening a lot for us," Orioles manager Buck Showalter said of the stunted offensive performance. "Our approach in those situations hasn't been good. We did a lot of things to create those opportunities, but we've got to cash those in. Two solo home runs in this place is not going to end up in the 'W' column very often."

The usually reliable Johnson (5-2) got into trouble by allowing two walks, an RBI single by Josh Hamilton and an RBI double by Adrian Beltre.

"I didn't make any good pitches, obviously," Johnson said. "I didn't make any pitches to get out of there. I had a chance. Hamilton beat me there, and that's probably not the guy you want to have beat you."

Showalter wouldn't pin the loss on Johnson, saying: "I just think he's human. We expect perfection out of him and Koji [Uehara] and Kevin [Gregg], it seems like every time out. One-run ball game, there's not a lot of margin for error there."

The Orioles have allowed four runs or more in 13 consecutive games, the longest such streak in the majors this season.

The Rangers' go-ahead run scored on the Orioles' 18th error in their past 22 games, when left fielder Nolan Reimold grabbed Hamilton's diving liner and two-hopped a throw into third base that Mark Reynolds could not handle.

Elvis Andrus raced home from third on the error by Reimold, who is expected to get more playing time in the field now that outfielder Luke Scott has been placed on the disabled list with a shoulder tear.

"I actually got a good break on it. If you dive for it, the ball gets by you, the bases clear, so I kept it in front, threw it to third. I don't know what really happened," Reimold said. "He slid, I think it might have hit him when he slid, I don't know. I didn't think it was a bad throw, it just got there the same time he did. The ball got away so, [it was] unfortunate."

Hamilton's hit and Andrus' scampering ensured that Atkins wouldn't pick up his first big league win.

Atkins, 25, wasn't exactly flawless. He allowed a base runner in each of his first four innings. He had just one perfect inning, the fifth. But he mixed a low-90s fastball and a sharp cutter to get the hot-hitting Rangers to continually roll over for groundouts or hit meaningless pop-ups with men on base.

"I have got a few pitches I can throw in different counts and I trust in my catcher and what he put down, and that really helped," said Atkins, who lasted six innings, giving up one run -- on Nelson Cruz's RBI single in the sixth -- on eight hits. He struck out five and threw 90 pitches (58 for strikes)

"He had a little, not even anxiety, just normal stuff that a 25-year-old guy making his debut with the Orioles would have," Showalter said. "I liked the way, it felt right about in the third inning, he seemed to settle in and get into a nice tempo. I'm real proud of the way he pitched."

Three of Atkins' first four pitches of the game were balls, but he didn't walk a batter. Throwing strikes had been Atkins calling card at Triple-A Norfolk. He allowed 16 walks in 461/3 innings for the Tides, and 10 of those came in two games. In six of his eight starts, Atkins walked two or fewer.

For the most part, though, the right-hander has been a bit of a mystery in the Orioles' organization. He was signed to a minor league deal this past winter after making seven relief appearances over two seasons for the Chicago Cubs.