Daniel Murphy prefers standing up when facing the media, but on Saturday afternoon, after handing his crutches off to a Washington Nationals employee, he took a seat to take questions about his left knee and his status for the 2018 season. Eight weeks after undergoing microfracture and debridement surgery on Oct. 20, Murphy declined to talk timetables because failing to meet the expectations, he said, would cause unnecessary alarm. So, while General Manager Mike Rizzo and Manager Dave Martinez have said Murphy is on track to be ready for Opening Day, the Nationals second baseman kept it vague. “I’ve had people who are really, really smart in the industry say, ‘You’re going to be healthy if you treat this the right way. If you’re sensible about it,’ ” Murphy said. “So that’s the goal right now. Just to be smart with it. I’ll be ready to play when it tells me I’m ready to play.” Murphy said he didn’t know if it was an acute injury or whether wear-and-tear produced it. He recalled he initially noticed something was wrong with his knee over the final three games against the Chicago Cubs in the National League Division Series, but said he didn’t believe the pain hindered his performance. He batted just .211 in the five-game series, though he went 2 for 5 with a home run, a double and two walks in Game 5.