The New York Mets altered their catching depth chart ahead of Thursday's game against the Chicago Cubs, activating Tomás Nido from the injured list and designating Gary Sánchez for assignment. Arguably the most notable aspect of those transactions is they ensure youngster Francisco Alvarez will remain part of the big-league roster.

Nido, 29, has been sidelined since early May because of vision problems related to dry eye syndrome that he believes developed as a complication from his past LASIK eye surgery. He underwent a procedure that helps his eyes remain lubricated. "It's kind of alleviated the eye pressure that I had," Nido told reporters last week, including "I felt like I had somebody pushing on my head. I had a headache for like 72 hours straight."

Nido had appeared in 19 games prior to being placed on the shelf, hitting .118/.148/.118 (minus-24 OPS+) with no home runs or extra-base knocks. He has never been much of an offensive threat, but it's fair to think his vision problems impacted his ability to do damage. 

Sánchez, 30, appeared in just three games with the Mets. He went 1 for 6 with a run batted in and zero extra-base hits. He joined the organization earlier in May after being released by the San Francisco Giants. It's unclear if he'll find another big-league gig, or if he'll accept a minor-league assignment. 

Alvarez, 21, has hit .253/.316/.506 (124 OPS+) with six home runs in 95 plate appearances. He entered the season ranked by CBS Sports as the No. 3 prospect in the minors. Alvarez figures to remain the most-days starter, as veteran Omar Narváez remains unavailable after suffering a calf injury in April.

The Mets will enter Thursday night's game with a 25-25 record on the season.