Parmelee for Span in the OF. How much will it cost in runs?
Trading Denard Span to get pitching was necessary. Taking the high upside/higher risk prospect was wise. It is very difficult to get a top starting pitching prospect.
However, I am concerned about the Twins plan for the outfield. Is Parmelee in RF the plan?
Denard Span was credited with saving 20 runs above average (1073 innings) as a CF last year. Ben Revere has a -4 for his career in CF (1123 innings). That is a -24 run change.
Ben Revere fares much better in RF saving 11 runs above average. It helps that the average RF is nowhere near the average CF. If Parmelee replaces him, how will he fare. It is difficult to know. I would think the Twins would be fortunate if he was in the -10 neighborhood. He has played very little outfield in the upper minors. Willingham was a -13 in LF in 2012. It would seem that Parmelee would be in his neighborhood defensively.
If the Twins lose around 20 runs to average in CF and another 20 in right field that 40 run loss represents a significant increase to runs given up. It Those additional 40 runs given up equate to 4 additional losses. Likely it won;t be that bad. I think Revere will be better than league average in CF. Thirty runs might be a more reasonable projection.
Poor defense has another huge impact on the team. Poor defense will also extend innings, burden an overworked bullpen and slow the development of young pitchers.
Data was taken from fangraphs.com (defensive runs saved)