In the top of the fourth inning - with the score still 1-0 Rangers - Adrian Beltre fouled a Doug Fister pitch off of his lower left leg. It was not the first time that Beltre fouled a pitch off of his lower left leg in the game, and he went down to the ground in obvious pain. He got back up, continued the at bat, and even put a ball in play, but it was a routine grounder to third, and he had trouble running it out. Beltre more or less limped towards first base, then limped towards the dugout where he was attended to by trainers.
Not to worry, though. After the inning (in which the Rangers didn't score, or even get a guy on base), Beltre reached for his glove and went out to the field. So he's not done yet. He's clearly in pain and if I'm the Tigers I bunt everything, literally everything to third base, but Beltre's a classic gamer and he's not coming out unless he absolutely has to.
It's worth noting now that Beltre once finished a game despite sustaining a damaged testicle earlier on. It's not that Adrian Beltre lacks pain receptors. It's that Adrian Beltre does his best to ignore what his pain receptors try to tell him. Shut up and mind your own business, pain receptors!