Beltran alerted Matheny to some soreness and stiffness in the limb on Sunday, prompting Matheny to hold Beltran out of the starting lineup for the series opener. Beltran iced his knee throughout the day and said after Monday's game that he felt it improve throughout the day.
That's why, when asked, Beltran told his manager he felt good enough to pinch-hit in the ninth inning.
"I iced a couple times and it got better," said Beltran. "I went to the [batting] cage and hit against the machine and soft toss. It didn't bother me at all."
While no one anticipates this being a serious ailment, there is reason to be extra cautious. Much of Beltran's recent injury issues have been concentrated in that knee. A bone bruise in the joint limited Beltran to 81 games in 2009. He had surgery on the knee the following offseason and played in only 64 games in 2010.
The team has characterized Beltran's knee injury as day to day. Beltran wouldn't speculate whether he'd be ready to rejoin the lineup on Tuesday.
"I have to come [Tuesday] and see how it feels," he said. "I can't make the decision right now."
Beltran, who flied out in his one at-bat Monday, has not had any issues with either of his knees since joining the Cardinals as a free agent in December and spoke just last week about how refreshing it was to have those ailments in the past.
"When I wake up in the morning, I feel no pain in my body," he said at the time. "I feel good coming to the ballpark. In the past years, you wake up in the morning and feel like your knee hurts. Right now, I'm not even icing my knees. I'm not putting ice on my body. It's not like I'm spending half of the day in the training room. I'm going to the [batting] cage and having a good time."
Though unable to start, Beltran was honored by Major League Baseball on Monday. He was named National League Player of the Week after hitting six home runs and driving in 13 over his last six games. He finished the Cards' loss to the Cubs leading the NL with 13 homers.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.