With Willingham and Burroughs in camp, only first baseman Justin Morneau and outfielder Oswaldo Arcia have yet to show before Thursday's official report date. Full workouts begin for position players on Friday.
"I'm excited," Willingham said. "The weather is great down here, so I'm ready to get rolling. I got a chance to meet most of the guys at TwinsFest, but that's it. So I look forward to getting to know guys and developing relationships and camaraderie."
Burroughs, who played in 78 games with the D-backs last season after being out of the Majors four years battling substance abuse, is expected to compete for a backup infielder role as a non-roster invitee. "I'm going show up and play hard, do what they want me to do," Burroughs said. "I think I'll have more versatility this year playing different positions, and I'll try to fill in at different spots. I'll just go out there and compete. It's a fun time of the season right now, just showing up and meeting new teammates and smelling that fresh-cut grass. I'm looking forward to it."