OAKLAND, Calif. – Brandon McCarthy is back to his Twitter-happy self, a positive sign for the Oakland Athletics’ pitcher struck in the head by a line drive this week.

McCarthy, 29, underwent two hours of surgery earlier this week to relieve pressure on the brain after the ball hit the right side of his head. He suffered an epidural hemorrhage, brain contusion and skull fracture.

McCarthy’s lighthearted posts came a day after trainer Nick Paparesta said McCarthy was still in a “life-threatening” situation.

McCarthy is recovering in a Bay Area hospital.

ORIOLES: Right fielder Nick Markakis will be out for at least six weeks because of a broken left thumb, the result of being hit by a pitch from Yankees left-hander CC Sabathia.

Markakis left Saturday night’s 5-4 win over the Yankees in the fifth inning immediately after being struck by the pitch. The injury will keep him out of the remainder of the regular season and well into October — should Baltimore qualify for its first postseason appearance since 1997.

NATIONALS: All-Star ace Stephen Strasburg is done for the year after Washington decided to end his season following a shaky start, costing him a chance to possibly pitch in the playoffs.

Manager Davey Johnson made the announcement Saturday morning with the Nationals holding the best record in the majors. He said the media attention surrounding the innings limit for the 24-year-old right-hander was affecting the pitcher.

“I just told Stephen that his year is over. He’s had a great year. I know what he’s going through,” Johnson said. “The media hype on this thing has been unbelievable.”

Johnson said Strasburg was “emotional” about the decision to end his season immediately.

Strasburg went 15-6 with a 3.16 ERA in his first full season following elbow-ligament replacement surgery on Sept. 3, 2010. He struck out 197 in 1591/3 innings.

DODGERS: Center fielder Matt Kemp will miss at least the final two games of this weekend’s key series at San Francisco because of his troublesome left shoulder.

His shoulder is still bothering him from a crash into the outfield wall Aug. 28 at Coors Field.