Martin was traded from the Braves to the A's on July 2 and has pitched for Triple-A Nashville since. He made 21 relief appearances for Atlanta this season and posted a 2-3 record and 5.40 ERA.
"Got a mix of pitches, throws upwards of five different pitches," Melvin said before Monday's series opener against the Angels. "Got him from Atlanta, and not sure what to expect until tomorrow."
Martin, who is from Dos Palos, Calif., a small town about two hours southeast of Oakland, has never pitched in the Bay Area in his professional career.
Earlier this season, he was supposed to start for the Braves against the Giants. Nearly 50 friends and family planned to come to the game, but Martin was optioned three days prior.
The Braves called Martin up when the club went to Arizona a few days later. He ended up watching the game he was supposed to pitch in alone in his Atlanta apartment.
Martin kept getting messages and pictures on his iCloud, but he said he really just wanted to watch alone, in peace.
"I missed the one trip that I really wanted to pitch at, see some family and friends," Martin said. "But I'll have some people here tomorrow rooting me on."
He said he'll have 10-20 fans in attendance Tuesday, ranging from his parents, to other relatives, to his fiancée.
Though Martin came to a few A's games as a kid, he was mainly a Braves fan because his father, Chuck, played two seasons of Class A ball in the Braves' system.
Martin said his father was mainly a power pitcher, while Cody prefers to mix his pitches and keep hitters off balance. He said his best pitch is his curveball, but he's also worked on his slider, changeup and cutter.
"I can use all my pitches, which has gotten me out of a lot of jams," Martin said. "That's kind of my thing."
He said the main takeaway from his time in the Majors is that having a short memory is key.
Martin started to second-guess himself after giving up a walkoff homer to Bryce Harper in May, but he put the outing behind him and regained confidence.
"I'm not here to just coast through the month," Martin said. "I'm going to try and provide a little spark to this team."