In the bottom of the first inning, Teixeira writhed in pain on the ground after Boston's Jon Lester nailed him on his back knee in his right-handed stance.
X-rays on Teixeira were negative. Teixeira has a right knee contusion and likely won't play on Wednesday.
"It was very painful when it happened," Teixeira said. "I'm very lucky that it wasn't broke or anything. Hopefully, it will be just a day or two and I will be all right."
Yankees manager Joe Girardi said he didn't think Teixeira would play on Wednesday. Jorge Posada or Nick Swisher would start at first. During Tuesday's 6-4 loss to the Red Sox, Posada replaced Teixeira and went 3 for 3.
"If it hit right on the knee cap, it might do a lot of damage," Teixeira said. "I feel lucky in that regard."
Teixeira said it hit him a bit below the knee cap.
"My concern was that he fractured his kneecap," Girardi said. "Because Tex has been hit a lot in the three years that we have had him and I'd never seen him show that much pain before. He is tough. He has played with a broken toe. He was in a lot of pain. It was scary."
Teixeira entered the game hitting .258 with 18 homers and 41 RBIs. Teixeira has been hot of late as half of his homers have come in the previous 16 games.
"When you talk about him or Robbie (Cano), there are some guys that are irreplaceable," Rodriguez said.
He added: "I've never seen him in so much pain. It's definitely a scary moment. The last thing you want to think about is (losing Teixeira) for the season or 60 days. So many things go through your mind."
Three batters after Teixeira was injured, Lester hit Russell Martin with a pitch above the right knee. Martin walked to first base and did not appear to be hurt.
Lester said he was concerned for Teixeira after hitting him.
"It's tough to hit a guy like that and see him kind of go off the field not feeling too good," Lester said. "Too be able to get back up on the mound and throw strikes was key."
Andrew Marchand covers the Yankees for ESPNNewYork.com. Information from ESPNNewYork.com's Ian Begley and The Associated Press was used in this report.