But then, Mastroianni felt some tightness in his left hamstring while checking his swing on Feb. 28, and was shut down for more than a week before returning on March 9.
And a lot changed in that time, as Hicks had a breakout week, crushing five homers in a span of three games, including a three-homer performance against the Phillies in Clearwater, and a homer in an exhibition game against Puerto Rico.
But Mastroianni said he's tried his best not to be too worried about that race for the center field spot -- even with the way Hicks has emerged over the last two weeks.
"I'm not even thinking about it and I'm not going to say I don't care about it because I absolutely do, but I am who I am," Mastroianni said. "I'm going to go out there and play my game every day. My goal is to make this team and be on the flight to Minnesota, and help us any way possible with whatever role that may be. That was my plan last year and it worked pretty good, and so this year I want to continue to help this team win.
"So if it's me leading off and playing center, that's great. And if it's me coming off the bench like last year, that's great. We're here to win baseball games. There's no personal agenda for me. It's what's best for the Minnesota Twins. That's what concerns me."
Mastroianni's attitude is refreshing, as he knows how hard he's worked to be in the position he's in after joining the club before last season as a waiver-wire pickup from the Blue Jays.
After starting out the year in Double-A New Britain, Mastroianni emerged as a pleasant surprise for the Twins last season, as he hit .252/.328/.350 with three homers, 17 RBIs and 21 stolen bases in 24 attempts in 77 games last season.
Mastroianni also provided stellar defense at all three outfield positions and proved to be a solid fourth outfielder off the bench. And he's continued that this spring by hitting .412 with three stolen bases in eight games, which has impressed Twins manager Ron Gardenhire.
"He's going to get out there and look to take advantage and run," Gardenhire said. "And he's hit well. He had the little hamstring thing but he's back out there. He's a very aggressive player who brings that spark to the game."
Gardenhire added that with a little less than three weeks left until Opening Day on April 1 against the Tigers, it's too early to declare a favorite in center field.
But Mastroianni knows what he's up against, as Hicks is having a great spring and is regarded as one of the best center field prospects in the game, as evidenced by his No. 98 overall ranking by MLB.com.
Mastroianni, though, had nothing but positive things to say about Hicks, who was his teammate last season at Double-A New Britain for a short while.
"He looks like a totally different player," Mastroianni said. "He looks like the kid with all the tools, but he put it all together and he's brought it into the games with the way he's hitting. I'm happy for him with the way he's playing. He's worked hard and deserves that success."
But Hicks has yet to play above Double-A New Britain and Mastroianni proved last season he can handle Major League pitching.
Mastroianni's not as highly regarded as former Twins center fielders Denard Span or Ben Revere, but has plenty of speed and an acute sense of what his role is on the team.
"Throughout my career, I've helped my team by being on base whether it's walking or getting hits," Mastroianni said. "My presence on the bases is obviously my best attribute. Getting myself on base is key for me."
So Mastroianni said the goal is to continue to play his game the rest of spring and let the Twins make their own decision about who will be the center fielder come Opening Day.
"I've been pretty happy with the way things have gone so far," Mastroianni said. "I usually don't swing the bat well early in spring. So it's been nice to get some barrels on some pitches and do well."