WASHINGTON — Brandon Nimmo woke up face down on his hotel room floor around 5:15 a.m., Monday morning, not knowing how he got there and why his head hurt. Even worse, he was bleeding. In a scary incident, the Mets‘ left fielder fainted after getting up to use the bathroom and fell over, cutting his forehead in the process. Luckily, after getting examined at a Washington hospital, it was determined that there were no underlying issues and no concussion. The cut didn’t even require stitches — just a small bandage. However, he was ruled out Monday for the series opener against the Washington Nationals. “I’m not really sure why this happened,” Nimmo said Monday at Nationals Park before the Mets began a three-game series. “But what we were able to do was check all of the boxes. I called the trainers immediately when I had the cut, and I woke up and they came over. We started getting everything in motion. We went to the ER to get a CT scan, an EKG and all of the tests that we could think of in order to find out what this might be.” The doctors determined the cause to be vasovagal syncope. Nimmo experienced a leg cramp after he woke up which likely caused a sudden drop in blood pressure. “I got up to go to the bathroom, I cramped when I sat down, and I got up really quick and kind of like went to stretch it,” Nimmo said. “What they’re telling me is that it probably spiked my blood pressure and got the heart rate up for a little bit real quick. So I went and got a drink of water, and came back, and I wasn’t feeling that great stomach-wise. I was like, ‘OK, so now I don’t feel that great,’ and I started to get hot. Then I had a tingling in my palms and I’m thinking, ‘What am I going to do?’ “Then I was out.” Nimmo had not consumed any alcohol Sunday, but thinks the cramp was a result of playing in the humidity, getting warm again after a lengthy rain delay and failing to properly hydrate following the game, though he can’t really know for sure. What he does know is that fainting is somewhat common, something the medical staff at the ER informed him. “They were like, ‘This happens a lot. It’s more common than you think,'” Nimmo said. “It’s just weird for me because I’ve never fainted. There has never been a moment in my life that I could not get back.” Nimmo was diligent about calling trainer Joe Golia immediately. Manager Carlos Mendoza was informed early in the morning, waking up to a text message and a phone call from a trainer. “Every time you get a text or a missed call from a trainer, you know something is going on,” Mendoza said. “He called the trainers overnight and luckily, our trainers went to his room and were able to take care of it.” Nimmo has been tested for concussions previously this season after a pitch to the head in late May, but has tested negative each time. He doesn’t believe that this has anything to do with any past concussions. The Mets will play two men down Monday. Edwin Diaz remains suspended and Nimmo won’t be available off the bench for precautionary reasons. Nimmo spent several hours in the hospital and wasn’t able to sleep or eat Monday. Jeff McNeil made his fifth start of the season in left field in place of Nimmo. The Mets are hopeful he’ll be able to play Tuesday. METS TO CALL UP SCOTT Tylor Megill’s demotion leaves a spot open in the rotation this week, which the Mets will fill with rookie right-hander Christian Scott. “We’ve been saying he’s a big-league pitcher,” Mendoza said. “Where we’re at, especially needing a spot on our rotation, his time now.” The team sent him back to Triple-A Syracuse shortly before the London Series to monitor his innings. His starts were somewhat short but he threw 75-80 pitches his last time out to keep his arm stretched. Scott will face left-hander Mitchell Parker on Wednesday night in the third game of the series. TRAINER’S ROOM Right-hander Kodai Senga (capsular strain in right shoulder, triceps tightness) will make his first rehab start Wednesday with High-A Brooklyn, throwing 40 pitches. The Mets are trying to get him back into a schedule of pitching every sixth day, but they may need the entire month of rehab time allotted to build up their ace again.