PHOENIX -- When he flew to Pittsburgh last month to be examined for any lingering effects from the trauma he suffered when he was struck in the head by a comebacker on Sept. 5, Brandon McCarthy admittedly was wary.

The process challenged him physically and mentally to test multiple areas of his brain, particularly the parts that were affected when he was struck by a line drive off the bat of Angels shortstop Erick Aybar.

"I was sort of hesitant as to what I could do or what I was capable of, and then once they pushed me through it, I realized actually I think I'm fine," McCarthy said. "Ever since that day, I haven't been restricted by anything. I've felt no symptoms. Really it's become as much of a non-factor as something that major can be. I've resumed full workouts with no limitations. Haven't had even the slightest hint of a setback."

What appears to be a full recovery made the D-backs confident in signing the former Oakland A's right-hander to a two-year, $15 million contract in the wake of last week's Winter Meetings.

McCarthy passed a physical administered by the D-backs earlier this week and said, at this point, he is under no physical limitations.

"I came through that two or three days of testing to where everything was extremely normal -- where I tested right where I would have if I hadn't had the incident," McCarthy said of his examination at the University of Pittsburgh. "I expect it to keep going to where it's just something that happened in the past."

There were plenty of suitors for McCarthy, who was 8-6 with a 3.24 ERA in 18 starts for the A's in 2012. What helped separate the D-backs from the pack was the familiarity McCarthy had with players like Trevor Cahill, Cliff Pennington and Brad Ziegler, all of whom he played with in Oakland.

In addition, McCarthy has family in Tucson and Scottsdale, so he is comfortable with the area.

Oh, and there's also the fact that he likes the D-backs' chances of being successful on the field. McCarthy joins a rotation that also includes Ian Kennedy, Cahill and Wade Miley, with the final spot being filled by one of the team's young pitching prospects.

"Actually, a big thing is it's a team that is so close to being so competitive and two years ago was an extremely competitive team, and I think all the ingredients are there for that," McCarthy said. "A really deep starting rotation, there's a lot of good offensive talent there, especially young talent. There's some good defensive players. I think you have everything you're looking for in a team that can possibly make a deep run and possibly win the whole thing."

McCarthy is known for being a good presence in the clubhouse, thanks in part to his humor.

In fact, McCarthy was even thinking up funny tweets he could send out while he was in the ambulance being rushed to the hospital after the Sept. 5 incident.

While he's close friends with Cahill, the two have distinctly different personalities, with Cahill being extremely quiet.

"If Cahill's the biggest personality you have on the staff, which I can't imagine he is, then you're hurting in that regard, because that guy is too quiet," McCarthy said. "So that's the one thing I try to do is bring him out of his shell and make him uncomfortable. He's told me nothing but good things about the other guys on the staff. I'll try to get in there and make fun of as many people as I can and hopefully not be hated and try to fit in."

A couple of years ago, McCarthy altered his mechanics a bit in an effort to reduce the number of fly balls he allowed. The change in arm angle, D-backs GM Kevin Towers said, gave McCarthy better life on his pitches.

By getting hitters to keep the ball on the ground, McCarthy has become better suited for a ballpark like Chase Field. Located at the second-highest altitude in the Majors, balls in the air tend to carry at Chase, making it a challenge for fly-ball pitchers.

"I think more of an emphasis of getting the ground ball is something that will help me, but it doesn't mean that it's a guaranteed victory there," McCarthy said of Chase Field. "A tough park is a tough park. It's still the emphasis on making pitches, making quality pitches. There is no fear of the stadium. A lot of that is talking to Trevor. You're going to give up home runs, you're going to give up some things that are a little bit cheap, but when you throw well, you're throwing well, and that will exist in basically any ballpark."