Teixeira was out of New York's lineup for its three-game weekend series against the Reds due to severely inflamed bronchial airways, but he pinch-hit in the ninth inning of Sunday's 5-2 loss, reaching on an error.
"Everyone knows I'm not 100 percent," Teixeira said. "I've just been really trying to grind it the whole season, really. It makes you really appreciate when you are healthy.
"I'd love to be able to say that I'm 100 percent and strong, but I haven't really been driving the ball like I should be this year. It has been a rough go. It really doesn't matter where I hit anyway."
Teixeira entered Monday's game against the Royals batting .226 with five home runs and 20 RBIs. He had not batted seventh in a starting lineup since 2003 as a member of the Texas Rangers, and manager Joe Girardi said he checked with Teixeira before filling out the batting order.
"I think you always have a little bit of a worry; you always have to be concerned how a player handles it," Girardi said. "You talk to them, you feel them out, you listen to what they're saying. I'm not so sure we would say Mark likes it, but he said OK, and I asked him a couple different times."
Teixeira said he has done away with all medication for his cough, which has left his voice raspy. Of more concern is that physical activity could bring back his coughing fits, though running out a ninth-inning grounder off the Reds' Aroldis Chapman on Sunday did not seem to trigger a recurrence.
"I'm curious to see the first time he has to run hard a couple of times, what happens," Girardi said. "He had to run hard to first yesterday, and I did not hear him cough."
Girardi said that one byproduct of dropping Teixeira in the order could be that he takes less heat for the Yankees' struggles with runners in scoring position; as a club, New York entered play on Monday with just six hits in its last 59 at-bats with runners at second or third base.
"Maybe just people will stop asking him so many questions all the time," Girardi said. "He's been the focus of our lineup, and if the other guys were hitting, he probably wouldn't be a focus. There's a lot of other guys who are struggling in those situations, some worse than he is."
Teixeira said that he still believes he will be able to approach his normal levels of production, which peg him for at least 30 home runs and 100 RBIs by season's end.
"Oh yeah, [the numbers will be there] because they always are," Teixeira said. "No one has been more consistent than me. I feel like I'm getting a little bit better. I know that I can get back. We may need to take some time off like we did this weekend every now and then if my stamina isn't there. It's a day-by-day thing."