Nats’ Scherzer in doubt for Game 1

Just because the Cubs announced their rotation order for the first round of the playoffs doesn’t mean the shape of either team’s pitching staff is especially clear.

On Wednesday, Nationals manager Dusty Baker again declined to declare a Game 1 starter, even though ace Max Scherzer’s strained hamstring kept him from throwing the bullpen session he said he had planned.

When Scherzer merely threw on flat ground, it seemed to make clear the Nationals’ intention of pushing him back to a Wrigley Field start in Game 3 or 4 next week — and made it even more obvious that red- hot Stephen Strasburg would start Game 1 on Friday against Kyle Hendricks.

That could set up a Game 4 matchup of Scherzer and Jake Arrieta, Cy Young winners who might have started the opener if not for their similar hamstring injuries.

And that could put a premium on a sweep for the series winner, getting significant extra rest for its key right- hander.

Meanwhile, for the Cubs, Arrieta’s status also puts an emphasis on the playoff bullpen.

The Cubs have tentatively made their decisions, team president Theo Epstein said, but weren’t ready to unveil a roster.

World Series veteran John Lackey, who was left out of the playoff rotation, has volunteered for bullpen work and could prove an important asset if Arrieta is forced out of his start early.

“We’re looking at him certainly as a viable option out of the pen, but we’re not prepared to announce the roster yet,” Epstein said. “Jake had a great day [ throwing Wednesday], but I think you’re always looking for as much depth as possible, and that’s on both sides of the ball.”

Lackey has three World Series rings as a starter for three organizations. What could he bring out of the bullpen?

Command, experience and aggressiveness for a few things.

“I’ve seen Lack come out of the bullpen and get a hold in a World Series [ in 2013],” longtime teammate Jon Lester said. “That’s one person I’m not worried about.”