Beltran said he arose feeling "like with something on my eye."
He suspects pinkeye (conjunctivitis) is the cause of the slightly blurry vision and pressure. The right fielder is unsure when he will return to game action.
Trainers took images of Beltran's right eye and sent it to team doctors for review. He was given eye drops. The team officially is only labeling it right eye inflammation.
"They say it could be conjunctivitis," Beltran said. "They gave me some antibiotics today. It's better, but I still feel a little blurry. They got me some eye drops and they want me to take those tonight, and hopefully tomorrow I'll feel better. ... I feel better than how I came here [earlier], but I still need to get better in order for me to play."
Fernando Martinez, who hit a pinch-hit two-run homer Friday as the Mets rallied for a 6-4 victory, replaced Beltran in the starting lineup.
Martinez went 1-for-4 on Saturday.
Adam Rubin covers the Mets for ESPNNewYork.com.