The initial diagnosis is a sprain, which occurred after Machado's knee buckled as he swung at a pitch from Yankees starter Chris Capuano in the third inning. Machado fell on his back and writhed in pain, clutching the knee as head athletic trainer Richie Bancells and manager Buck Showalter rushed out of the dugout.
Machado was able to walk without crutches following an 11-3 win over the Yankees before 34,018 at Camden Yards. He was part of the handshake line on the field and later stopped by Showalter's office.
"He's got an MRI in the morning at 10 and we'll have hopefully some information at what we're looking at," Showalter said. "It's been a lot more positive than the way it probably looked. I just got through talking to him a little bit. He had 100 people around him up here with him probably. Obviously, we had a game going on. But he seemed in pretty good spirits considering.
"He's had some experience with it. We're hoping for good news tomorrow. There's a chance we may have dodged a bullet. We'll see."
Machado underwent surgery on the left knee in October and missed the first month of the season. His other knee buckled tonight as he grounded out to short, his bat shattering in the process.
"I haven't had time to look at (the replay)," Showalter said. "I've heard a couple people talk about it, but I try not to talk about something I'm not sure of. I'll leave it in the doctors' hands. I'll probably take a look at it before I leave tonight.
"It kind of reminds you of the torque and things that go on all season long. People who play a lot of games and the angles you're at, it's a wonder... It amazes me the games these people are able to play as it is."
Machado didn't seem overly concerned after the game, which Showalter also took as a positive sign. He told reporters that the X-rays looked good.
Machado's spirits were "as well as can be expected," Showalter said.
"He was in the line after the game and walked in my office and we talked a little bit. If you've been through what he'd kind of been through in the past, that initial feeling is pretty negative. But the doctors have looked at it and everything. He's getting some best-case scenarios that we're going to dwell on until the MRI says something different. We'll see."
The Orioles' resiliency was on full display again tonight. Machado's replacement, Chris Davis, hit a two-run homer in the fifth to give the Orioles a 4-3 lead and they piled on the Yankees.
"I'm very proud of them, but guys don't live in that gloom and doom," Showalter said. "Obviously, we all think the world of Manny and know how much it means to him. He's a good player on our club, but the game doesn't stop. It doesn't stop when Brian McCann has a concussion, it doesn't stop when (Masahiro) Tanaka gets hurt. I mean, the game goes on when we lose players like everybody does. We're not going to get caught up in that gloom and doom and the sky is falling.
"Hopefully we don't have to DL him and he's back in a few days. Who knows? That's the way I look at it. Same way with J.J. (Hardy). Maybe he comes in tomorrow and ready to go."
The Orioles may bring up an infielder from Triple-A Norfolk in case Hardy and Machado are unavailable Tuesday night. Steve Lombardozzi, Jemile Weeks and Jimmy Paredes are candidates.
"We don't have to," Showalter said. "It's certainly something we're considering. I was looking at it in the dugout. We actually looked at it before the game because we had a similar subject matter where J.J. was concerned if we had to go there. Dan (Duquette) and I will talk shortly. Probably want to talk to Brian (Graham) and R.J. (Ron Johnson) tonight and see where we are. Make sure if we have to bring somebody that they're ready to go, too."
Miguel Gonzalez's start at Norfolk has been pushed back from Tuesday to Wednesday.
"If we DL somebody, we could legally get him back," Showalter said.
The comeback and lopsided score made it easy to forget the botched rundown in the second that resulted in two errors and two Yankees runs.
"Everything's fine," Showalter said. "There's a runner at third with two outs, you're usually waiting until the ball gets in the first baseman's hand and move him back that way. That's what happened. So it was a little unexpected to see them try it with one out. They may have had a missed hit and run, I'm not sure. That pitch that he couldn't put in play.
"Because of the new rule, Caleb got anchored in there and straddled the plate. You've got to get up the first base line and give Manny a throwing lane. He's out if we get a throwing lane."
Bud Norris threw 62 pitches in the first two innings, but he made it through the fifth at 108 and picked up his 10th win. He's won his last six starts vs. the American League East and is 6-1 with a 2.62 in nine outings against division opponents.
"It wasn't like he was overly wild," Showalter said. "There were a lot of borderline pitches. Ask Darren (O'Day). You don't want to give in there, but a lot of foul balls. That's one thing they do, they grind at-bats and get deep in counts. If you don't put them away, you're going to have a bunch of slow innings. Kind of a challenging pace to the game."
The Orioles have scored in double digits in three of the last four games. They still haven't lost consecutive games since June 28-29 against the Rays.
The Yankees fall seven games behind the Orioles in the AL East. The Blue Jays are 5 1/2 back as they play in Seattle.
The Orioles are 68-50 overall and 33-26 at home. They're 29-19 vs. the division.
Jonathan Schoop's home run tonight was his 10th of the season and first at home.