Chen's gem, backed by a slump-busting offensive display highlighted by Nolan Reimold's three-run homer, halted Baltimore's backslide with a 6-1 victory over Texas, giving the club its third win in nine July games.
"It's big. For the last year-and-a-half, he was a consistent force for our rotation," catcher Matt Wieters said of an Orioles team that improved to 11-0 when Chen goes at least seven innings. "You know he's going to go out there and give you everything he has and compete. You want that guy going on the mound as much as you can."
Pitching in a Major League game for the first time since exiting May 12's start with the injury, Chen showed no signs of rust, lowering his ERA to 2.82 and improving to 4-3 in nine starts this season. The win, in front of 19,344 at Camden Yards, marked the Orioles' 50th of the season and is the first time since 1997 that Baltimore has reached the 50-win mark before the All-Star break.
"I don't know about anxious, it's just back in your element," Orioles manager Buck Showalter said of the vibe around Chen, who he challenged to go get a win in his second rehab game at the team's Double-A affiliate. "I think his last start was important in Bowie, he really got competitive juices flowing. It's been frustrating for him, I think, seeing us be challenged some, and the department that he brings.
"I know he's been anxious to get back with the club and make a contribution. It's been a tough, tough road for him."
And Chen came out firing. The lefty struck out three of the first five batters he faced and didn't allow a hit until Adrian Beltre's two-out, fourth-inning single. The impressive seven-inning outing kept the Rangers in fits, with Texas' lone run coming on Beltre's fielder's choice, a would-be double play ball that third baseman Manny Machado double-clutched in the sixth.
"I proved myself tonight," Chen said through interpreter Tim Lin. "I'm healthy, and I'm back. I feel like I help the team to win. Everything is for the Orioles."
The only Orioles pitcher to make at least 20 starts last season, Chen battled through the Baltimore humidity and needed just eight pitches to get through a perfect seventh inning and cap a 100-pitch start that was the most he had thrown in a game since April 26.
"As he got deeper in the game, you could see he was laboring a little bit," Rangers manager Ron Washington said. "But the guy had a pretty good fastball that he moved around and a breaking ball and a changeup. He threw the ball well. He hadn't pitched in awhile, but it certainly didn't look like it out there."
Chen's efforts energized a lethargic Orioles lineup, which lit up Rangers spot starter Josh Lindblom for six runs on nine hits and four walks. The O's struck first in the third inning, with Machado delivering an RBI triple and scoring on Lindblom's wild pitch. The 21-year-old Machado had three hits in the win, extending his own Major League high to 14 games with three or more hits.
Reimold took care of the rest. After Wieters and J.J. Hardy worked walks to start the bottom of the fourth inning, Brian Roberts hit a long RBI single off the center-field wall. The hit, which grazed Engel Beltre's glove, was put under review to see if it cleared the fence, but the ruling was upheld. There was no second-guessing Reimold's blast, as the Orioles designated hitter -- a late lineup addition given Chris Dickerson's left shoulder strain -- sent Lindblom's first-pitch 88-mph fastball down the left-field line to push the Orioles' lead to six.
"It felt good that I was able to come through one time," said Reimold, who was activated from the disabled list July 2 and hadn't homered since May 4. "Something to build on and glad to get the win."
Orioles reliever Tommy Hunter put the finishing touches on the win, tossing a 1-2-3 eighth inning and getting Elvis Andrus to ground into a game-ending double play.
"I don't know that it was a do-or-die night, but when you're playing somebody who's up in the standings, it's never too early to look beyond that, too," Roberts said. "When you're playing head to head, you need to get wins against teams that are right there with you or ahead of you. So I think tonight was important."