BALTIMORE (AP) - Adam Rosales would have preferred to celebrate his return from the disabled list with a victory.
Instead, he had to settle for personal glory during an otherwise dreary night for the Oakland Athletics.
Rosales homered in his long-awaited first game of the year, but that was the extent of Oakland's offense Monday night in a 4-2 loss to the Baltimore Orioles that extended the A's skid to a season-high seven games.
Rosales had been sidelined since spring training with a fractured right foot. He came off the 60-day DL on Monday, promptly joined the starting lineup at third base and hit a two-run shot to bring Oakland to 4-2 in the fourth inning.
"It was good to get back and try to help the momentum a little bit," he said. "I was a little nervous, but it felt good to go all nine. There was a lot of adrenaline to hit a ball like that. It was exciting."
Rosales contributed on defense, too - no small accomplishment for a team that started the day with 43 errors, second-most in the AL.
"Obviously that homer was exciting. It got us back in the game," manager Bob Geren said. "He also made a great play at third. I like the energy he brings and the talent also. Very nice impact the first game. It was a losing cause but he was a highlight reel."
Brian Matusz and three relievers combined on a seven-hitter to help Baltimore beat Oakland for only the fifth time in the last 25 meetings.
Matusz (1-0) allowed two runs and seven hits in 5 1-3 innings in his second start of the season. He spent the first two months on the DL with a strained left oblique muscle.
The 24-year-old was lifted in the sixth after giving up successive one-out singles to Kurt Suzuki and pinch-hitter Scott Sizemore, who was recalled from Triple-A Sacramento hours earlier. Jim Johnson entered and got Rosales to bounce into a 1-6-3 double play.
Johnson retired the side in order in the seventh, Koji Uehara worked a perfect eighth and Kevin Gregg got three straight outs for his 11th save.
"It's a lot of fun playing like that," said Matusz, who has won seven straight decisions dating back to last August.
Matt Wieters had two hits, an RBI and scored a run for the Orioles, who took a 4-0 lead after two innings against Gio Gonzalez (5-4).
Gonzalez gave up four runs, three earned, and nine hits in seven innings. He permitted only three hits over his last five innings.
"Once I started getting in the groove I started attacking the zone," Gonzalez said. "It's just one of those situations - they're aggressive, they're swinging the bats, they just got a bunch of hits."
It all added up to the 15th loss in 19 games for the A's, who fell a season-worst seven games under .500 (27-34).
"Each one it's something different," Geren said of the slide. "The majority were well-pitched games. Tonight we got two runs. It's a combination - we haven't played well the past week, the total package. We have to play better."
The Orioles took a 1-0 lead with an unearned first-inning run. After shortstop Cliff Pennington muffed a potential double-play grounder, Vladimir Guerrero hit a two-out RBI single.
Baltimore made it 4-0 in the second. Derrek Lee led off with a single, stole second and continued to third on an overthrow by Suzuki. Wieters followed with an RBI single, J.J. Hardy singled, and both moved up on a wild pitch before Nolan Reimold hit a sacrifice fly and Nick Markakis singled in a run.
The A's two errors gave them 45 for the season. Oakland started the day with the second-most errors in the AL, two behind Texas.
Rosales connected in the fourth with a man on. It was his first home run since July 18, 2010, at Kansas City.
NOTES: Oakland 2B Mark Ellis left in the sixth inning with a right hamstring strain. ... To make room for Rosales and Sizemore on the 25-man roster, the A's optioned third baseman Kevin Kouzmanoff and right-hander Fautino De Los Santos to Sacramento. ... Markakis has hit in 160 consecutive series, the longest active streak in the majors.