Martin Maldonado is poised to potentially leave the Houston Astros. The star catcher is a free agent, so he has his choice of the 30 MLB teams. Right now, there are reportedly four teams interested in the backstop.
Martin Maldonado is widely heralded as one of the best defensive catchers in the game. His game calling has led to a few no hitters over the past few years and he routinely grades well in defensive metrics. His offense leaves a bit to be desired, but teams know what they're getting with the veteran.

Joining the hunt is another AL West team in the Los Angeles Angels. Bob Nightengale reported that the team has expressed interest, as has the Chicago White Sox, San Diego Padres and Miami Marlins.
Martin Maldonado free agency includes a hot market
With as many as four teams expressing interest in adding Martin Maldonado to their roster, the market for the veteran catcher is very hot. There aren't a ton of catchers available, and Maldonado is a veteran World Series winner who provides good defense and leadership.

That has piqued the interest of the aforementioned teams, who might be able to sign him as a relatively cheap addition to bolster their catching depth and defense behind the plate. Teams that havs young or inexperienced pitching staffs might be interested in his game calling as well.
Beyond those four major teams, there is a third party who could be interested. The Astros, understandably, are another team showing a bit of interest in bringing him back. They're familiar with him and he's done very well with the pitching staff they have put together.
They do have Yainer Diaz waiting in the wings (he packs a bit more offensive punch), but they obviously like Maldonado. He's been a part of their roster for a while, and the home team always has a chance of re-signing a player.
Nightengale did not suggest that a deal is necessarily imminent, but there is early interest in Maldonado as of now.