McDonald, 38, is battling to hang onto his roster spot after an offseason in which the D-backs stocked up on shortstops.
Even assuming that Didi Gregorius starts the year in Triple-A, McDonald could still find himself in a numbers crunch at the end of camp with Cliff Pennington and Willie Bloomquist figuring to make the roster and Eric Chavez and Eric Hinske being kept as backup infielders and pinch-hitters.
McDonald said he looks at the situation as a positive for the team.
"Defined roles are great, but it's unrealistic to think that's going to happen every year," McDonald said. "As far as an organization is concerned, you want as many quality players in the locker room, here in Spring Training and as close to the year as you can get. Whether in the big leagues or down in Triple-A, or Double-A, you just need quality players. You can't have enough depth at any position."
Other than being aware of the situation, McDonald does not focus on the roster issue.
"You control the things you can control," he said. "You control your preparation, how you go about playing the game and you try to make the decisions on our front office and coaching staff as hard as you can for them. It's great. If we start worrying about the things that you can't control, it's going to take away from your preparation and ability to be a good baseball player."
McDonald hit .249 in 213 plate appearances last year and appeared in five games at third, four at second and 54 at short.
Steve Gilbert is a reporter for MLB.com. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.