Even though Mercer was on Pittsburgh's big league roster from the middle of May on in 2013, sharing the shortstop job with Clint Barmes, he was entering new territory at this time last year. And that led to some uncertainty, even in his own mind.
"It was new to me, even in Spring Training," Mercer said. "I came in and I was the front-runner for the job, and I still didn't know what to do. I didn't really know how to prepare for an everyday gig."
After a slow start that saw him hit just .175 in April and .225 in May, he found his stroke. Five of his homers and 15 of his RBIs came during the month of June, and he had his best month of the season in July when he hit .319 in 26 games.
"It was rough at first. I'm not going to lie," said Mercer, who also spent a portion of the 2012 season with the Pirates (42 games). "It's something that I never experienced before, being a starter and being in the everyday role. There were expectations, even though I hadn't proven anything, even to myself.
"I had to look in the mirror, take a step back and realize, 'All right, slow down. Play the game the way you know how to play it and it will all work out.' Finally I got some things going. I strung some at bats together and kind of took off from there. I went through a lot of ups and down early, but through the middle of the summer I got hot, and then stayed even keeled for the rest of the year."
When Barmes (91 starts) and Mercer (63 starts) shared the shortstop job in 2013, the view held by many was that Barmes was the defensive guy and Mercer was the offensive guy. But Mercer proved he's not a one-dimensional player in 2014 when his .982 fielding percentage was the fourth-best mark among National League shortstops.
"That was very important to me," he said. "The truth is, my whole life I've always been more of a defensive-minded guy, and I still am. There's no doubt about it, I take pride in my defense. If you can play defense in this game, you can play for a long time. Somebody will always want you because you're good defensively."
Mercer is grateful that Pirates Manager Clint Hurdle stuck with him when he wasn't hitting the ball with authority early last year, and he's pleased to have made important contributions to a team that qualified for the playoffs for the second straight year in 2014.
"I learned a lot last year, and that's going to help me out going into this year," Mercer said. "Last year definitely gave me all the experience in the world. I'll be a lot more prepared going into this year."
This week the Pirates officially open Spring Training camp in Bradenton, Fla., with an eye on wrestling the NL Central title away from the St. Louis Cardinals. Pittsburgh has been a close second to the Redbirds the past two seasons, finishing three games behind in 2013 and two games back last year.
St. Louis has set the standard in the division, and the league, really, in recent years. The Cincinnati Reds and Milwaukee Brewers almost always play the Pirates tough, and the Chicago Cubs -- who have finished last the past couple of seasons -- have improved themselves with the addition of players such as catcher Miguel Montero, outfielder Dexter Fowler and pitcher Jon Lester.
"Our division is going to be one of the toughest there is," Mercer said. "It has been the last few years, and everybody is trying to keep up. Different teams are adding different pieces. That just keeps adding to how tough our division is. But it's going to be a lot of fun. It really is. It could be tougher [this year], but we're ready for the challenge."