Second base in 2013 was manned by the Pittsburgh Kid, Neil Walker. Walker provided solid numbers in 2013, slashing .251/.339/.418 with a .333 wOBA, and 115 wRC+. Walker hit for decent power with 16 home runs (marking the fourth straight year in a row he hit at least a dozen) across 551 plate appearances with a .167 ISO. He also struck out just 15.4% of the time with a healthy 9.1% walk rate. The switch-hitter was among the top hitters among his peers at his position, ranking sixth in wRC+, seventh in OPS, and ninth in wOBA among second basemen with 500+ plate appearances.
Although Walker would go down in Pirate history as arguably their best hitting second baseman, defense wasn't his calling card. 2013 was no different as he had zero DRS, but -3.8 UZR/150. This was one of his better defensive seasons at second as it's the only year he didn't grade as a negative defender in defensive runs saved, and was his third best single-season UZR/150 mark. Walker still was a key player for this 2013 team.
While the 2023 players could have a top prospect at the keystone by the end of the year, they'll go into the season with Rodolfo Castro manning the position. Castro is coming off a relatively solid rookie campaign in which he batted .233/.299/.427. Power is Castro's calling card, and he hit 11 home runs in just 278 plate appearances, with an ISO approaching .200 at .194. But in terms of plate discipline, Castro had a 7.9% walk rate and 26.6% strikeout rate. All told, he had a .315 wOBA, and 103 wRC+. But Castro was great in the home stretch of 2022, owning a .797 OPS, .342 wOBA, and 121 wRC+ from August 10th onward.
Castro's second base defense was mediocre at best. In just 236 innings, he had -2 DRS, -3 OAA, and a -9.2 UZR/150. Granted, the Pirates did move Castro around the diamond in 2022, giving him over 150 innings at shortstop and third base. However his fielding has never been considered a particular strength of his.
Now if Castro continues to hit like he did in August onward, and hits his offensive ceiling, then he'll be a better hitter than Walker was in '13. However, Walker was much more proven going into 2013 than Castro is going into 2023. Walker had three previous seasons where he had a 106 wRC+ or greater. For now, I'd give Walker the slightest edge. However, I 100% believe that could change by the time summer rolls around this year.