David Ortiz held the bat over his head as he walked slowly back to the dugout in the eighth inning Saturday afternoon, the line drive he hit having resulted in an out.

A man who normally shows only joy on the field, Ortiz pulled the bat down over the top of his helmet in a burst of frustration until it splintered in half.

“That’s the way I feel right now,’’ he said. “When things are going good, they’re going good. When they’re going bad, they’re going bad. That’s baseball in general. That’s one part of baseball that I’ll never figure out.’’

There’s a lot of that going around with the Red Sox, who were beaten, 8-2, by the Baltimore Orioles. A team that only a week ago appeared to have steadied itself is sliding away again, having lost four straight and five of its last six.

At 11-15, the Sox are falling deeper into last place with a lineup left thin by injuries and a pitching staff with a collective earned run average of 5.44, the second worst in the game.

Their performance at Fenway Park has been an embarrassment, with nine losses in the last 10 games.

It’s part of a trend. As Kirk Minihane of WEEI pointed out on Twitter, the Patriots have had nine victories at home since last Sept. 1 and the Red Sox eight.

When asked about the team’s performance at Fenway before the game, manager Bobby Valentine tried to smile through what has been a painful and dispiriting return to the major leagues for him.

“We have played well at home,’’ he said. “We just haven’t won the games that we could have won.’’

There was more of the same rationalization afterward.

“They got a lot of balls that fell in here and we got a lot of balls that they dove and caught,’’ Valentine said. “It’ll all catch up with us. Our balls will fall and we’re going to win a lot of games at home.’’