According to ESPN, "Free-agent catcher Gerald Laird has agreed with the Arizona Diamondbacks on a one-year, minor league contract that includes an invitation to major league spring training camp." The catcher turned 35 in November, and spent the last two seasons in Atlanta. He's very much a backup at this point, having averaged fifty games over the past four seasons, and you shouldn't expect much offensively. A career .244 hitter, he slumped to a line of .204/.275/.257 for the Braves in 2014, and Fangraphs project a ..624 OPS for him in 2015, and 0.1 WAR in 70 plate-appearances.
There's no shortage of options for the Diamondbacks at catcher this year, but the problem is, all of them have major question-marks. Tuffy Gosewisch was a rookie at age 31, and has only 55 major-league games to his credit, with a career OPS+ of 41. Rule 5 pick Oscar Hernandez hasn't played above A ball. There's general agreement that prospect Peter O'Brien has the lumber for the position, but there are frequent doubts about his defense and he's also extremely raw, with only 277 games as a professional. Now we have Laird, who has been close to or below replacement level (depending on the metric) since the beginning of 2010.
The team seems to be putting their faith in O'Brien for the long-term, and it appears will give him a shot in spring training to prove he's able to handle the job for 2015. If he does, Gosewisch will likely be the back-up, and I guess we'll have to try and stash Hernandez as the 25th man, or figure out a trade with the Rays for him. If O'Brien is deemed not ready for prime time, then it will probably be Gosewisch and Hernandez, with Laird ready to step into the breach, in the event of injury, or if Hernandez simply isn't able to cut it in the majors.