"It's a great social network," Parker said. "A week after I got traded, everyone was welcoming me."
Now Parker competes for a job in the A's rotation, which will be no easy task for a pitcher who missed the entire 2010 season while rehabbing from Tommy John surgery before bouncing back last year.
The 23-year-old Parker joined Oakland with big credentials, as the centerpiece in the December deal that sent Trevor Cahill and Craig Breslow to Arizona for Parker, outfielder Collin Cowgill and righty reliever Ryan Cook.
Parker was Arizona's first-round draft pick, ninth overall, in 2007, and he ranked as the system's top prospect from 2009-11. Despite those credentials, he had to re-learn how to pitch last season.
"Early in the year, the first month, month and a half, I was brutal," Parker said. "I struggled. I just wasn't the same. I fought through a lot of things, but I took what I learned from the failures and turned it into a pretty good second half."
After going 5-6, 4.87 prior to the all-star break in the Double-A Southern League, Parker went 6-2, 2.84 in the second half with Mobile. After helping the BayBears win the league title, he received a one-start September callup, pitching 5 2/3 shutout innings against the Dodgers. He even made the Diamondbacks' playoff roster, appearing as a reliever in one game against the Brewers.
"From where I came from early in the year, it was big," Parker said. "I tried to build on each and every start to that point. Obviously, I've still got a lot to figure out and to make myself better."
Parker added a two-seam fastball last year to mix with his mid-90s four-seamer, slider, curve and changeup. He made a big impression in the early days of spring training camp.
"I'm very impressed in the short time I've seen him," pitching coordinator Gil Patterson said. "He has been energetic, passionate and precise.
"His fastball has life and command to both sides. He has an electric changeup—the ball bottomed out when it went to home plate."
• Third baseman Scott Sizemore tore the ACL in his knee an hour into the first workout of spring training, clearing the way for catcher Josh Donaldson to prove himself at the hot corner. He played the position exclusively in the Dominican League in the offseason.
• Farm director Keith Lieppman said that righthanders A.J. Cole, Blake Hasselbrock and Blake Treinen, all of whom spent last season in low Class A, made big impressions in a mini-camp before spring training.