This is the second of a seven-part Around the Horn series that will take a position-by-position look at the Pirates' projected starters and other options heading into Spring Training. Up next: Middle Infielders

PITTSBURGH -- The Pirates have long talked about defensive stability, particularly as it concerns the four positions up the middle of the field.

Anchoring that core next season will be middle infielders Neil Walker and Clint Barmes, a pair that should certainly provide formidable defensive coverage for a team that has many pitch-to-contact pitchers.

For Walker, the learning curve is sharply decreasing. After making the transition to second base in 2010, Walker showed noted improvement in the field last season. In fact, he made enough of an impression to be named one of three National League Gold Glove finalists this fall.

"For him to be a year-and-a-half-old second baseman and for him to be one of the most reliable second baseman out there is impressive," general manager Neal Huntington said. "He's always going to be challenged because he is bigger than most second basemen. He's taken ownership of that."

Though Walker committed just six errors in 156 games at second, his ultimate zone rating -- a statistic that measures how much better a player is than an average defender at that position -- did not rank in the top half of the league. So yes, there is ample room for Walker still to improve.

On the offensive end, Walker is expected to be a critical bat in the Pirates' lineup. He would seem an ideal fit somewhere between the third and fifth spots in the batting order after providing 12 homers and 83 RBIs in 2011. Walker's placement in the lineup will largely be determined by where Andrew McCutchen is slotted in.

Walker's batting average and on-base percentage both dropped from his rookie season totals, though some would contend that he was the Pirates' most consistent hitter all year. Still, he adapted well when pitchers approached him differently and should now be better prepared to handle the workload demanded during a full Major League season.

"I knew this second year was going to be difficult from an offensive standpoint," Walker said. "It was clear to me from the first series of the year that I was going to be pitched differently than I was last year. I was seeing more of a mixture of pitches -- more sliders, more breaking balls. I had to quickly adjust to that."

While Walker is set to start at second, the Pirates do have protection behind him should Walker get injured. Chase d'Arnaud and Josh Harrison both have experience at the position. Yamaico Navarro and Rule 5 pick Gustavo Nunez are also candidates to win a backup job.

Those same four infielders will serve as insurance at shortstop, where Clint Barmes is set to take over. Signed to a two-year, $10.5 million deal in November, Barmes replaces Ronny Cedeno, whose club option was not exercised after the 2011 season.

Barmes said the guarantee of playing shortstop was particularly appealing as he considered multiple offers this winter. As for the Pirates, their intent was to be aggressive in finding a shortstop who would be defensively sound. Barmes' UZR of 7.9 was tops among all NL shortstops in 2011.

"I wouldn't be where I'm at without my glove and without what I've done defensively," said Barmes, who spent last year in Houston. "I take a lot of pride in my defense. I've only gotten better every year that I've played."

Offensively, Barmes, 32, is likely to provide production comparable to what the Pirates got out of Cedeno. Barmes batted .244 with a .312 on-base percentage in 2011. He had 12 homers and 39 RBIs, and manager Clint Hurdle will likely plug Barmes into the seventh or eighth spot in the lineup.

Barmes' best offensive year came in 2008, when he hit .290 and drove in 44 runs in 107 games. In '09, he finished with a career-high 23 homers in 154 games.

"Ronny obviously played great defensively for us this year. There is no doubt about that," Huntington said. "Offensively, Clint brings more weapons to the table. He's going to be an additional presence in our clubhouse of some veteran leadership and some presence to help our young guys continue to grow and develop."

Both Barmes and Walker were among the players to voluntarily report to Pirate City in Bradenton, Fla., this week for an organizational mini-camp. This gave the pair their first chance to get on a field together and begin the process of developing some defensive chemistry.