WASHINGTON — Yoenis Cespedes’ hamstring strain is not as bad as the Mets first feared, general manager Sandy Alderson said Saturday.

Alderson, in a freewheeling pregame discussion in the Mets’ dugout at Nationals Park, said Cespedes could be ready to return in fewer than 10 days — although he added it’s tough to predict how long a player with a hamstring injury will be out.

“We don’t think it’s severe,” Alderson said. “The ultrasound didn’t reveal any significant damage. He was walking . . . quite a bit better the next day. We don’t know how long it will take. Hamstrings are difficult, but we don’t think it’s that serious.”

Cespedes suffered his second left hamstring injury in a week when he had to be helped off the field on Thursday at Citi Field after hitting a double. He was placed on the 10-day disabled list on Friday.

“Again, a non-serious hamstring strain could keep somebody out for a while,” Alderson said. “But we’re hopeful he’ll be back and ready to go in that 10-day frame or thereabouts.”

It’s the second straight season Cespedes has suffered a leg injury, rested, tried to come back, gotten injured again and had to go on the DL.

“He might just be susceptible to that kind of injury,” Alderson said. “Something he may be predisposed to . . . I didn’t have any concern about how it was handled, but I was a little disappointed because it was similar to a situation we had last year where we tried to keep him active and simply had to put him on the disabled list. We told ourselves that we wouldn’t let that happen again and it happened again. But I think that’s the nature of these injuries as well. I think the fact that there’s a 10-day disabled list instead of 15 gave us a little more latitude to try and see if he could get through it.”

advertisement | advertise on newsday

Alderson said the Mets might look at their conditioning and exercise programs to see if they can prevent these types of injuries.

One injury the Mets seem to have recovered from is Noah Syndergaard’s right biceps tendinitis, which caused him to be scratched from Thursday’s start. Syndergaard, who will pitch against the Nationals on Sunday, said on Friday that he “refused” the Mets’ request that he have an MRI.

“That’s not standard practice,” Alderson said. “But I can’t tie him down and throw him in the tube either.”

On the subject of the Mets’ other injured players, Alderson said Lucas Duda (hyperextended left elbow) could return tomorrow in Atlanta and Wilmer Flores (knee infection) could be back in a week.

Pitchers Steven Matz and Seth Lugo, who are out with elbow injuries, are supposed to climb on a mound for the first time in their rehab schedules and throw at 75 percent Sunday. The earliest either could return is the end of May, Alderson said.

Mets videos

“We’re all disappointed with our [10-13] record,” Alderson said. “And the fact that we’ve had some injuries, we’ve had injuries in the past. We still think we’ve got a pretty good lineup that has to produce, starting pitching has to be consistent and the bullpen needs to get sorted out.”