One of the big differences between the 2012 Nationals and the 2013 Nationals is going to be the presence of Denard Span in the Nats line-up instead of Michael Morse. Morse didn't have a big impact on the season numbers as he missed two months of the season, but when he did return the run production of the Nationals increased dramatically. Morse ended the season with 18 homers. The Nationals as a team hit 194, the second most in the NL. Denard Span has never hit more than 8 homers in a season, and his 162 game average is 6. There is no question that replacing Morse with Span is a loss of power, but that loses sight of what Span does bring.
When people think of anything their mind often jumps to what is ideal or what is the best. The two best leadoff hitters of all time were Ricky Henderson and Tim Raines. Both of those guys stole a lot of bases. Denard Span doesn't steal that many bases. His career high in stolen bases is 26. The best base stealer in 2012 was Mike Trout with 49. Denard Span isn't likely to steal 40+ bases in 2013 simply because he never has before. What Span does do is he gets on base. In 2012 leadoff hitters for the Nationals averaged a .325 OBP. The average for the National League was .319. Denard Span for his career is a .357 OBP hitter.
OBP from the leadoff spot was one of the Nationals biggest weaknesses in 2012. If Span can be his average self then the Nationals will be in a much better position than they were in 2012. More men on base means more base runners to drive in and also means the longer it takes for the Nats to use up their 27 outs. The other thing is that while Span isn't going to be among the league leaders in stolen bases the Nats best base stealer in 2012 was Ian Desmond with 21. If Span plays a full season he should be able to match and exceed that total giving the Nats a new dynamic to their offense.
There is a little misconception to the stolen base. Most people believe the success rate needs to be around 75% as the break-even point, but that number comes from research done in 2004 by Joe Sheehan. Those numbers are perfectly valid, but they are perfectly valid for 2004. In 2004 the average NL team scored 751 runs. In 2012 the average NL team scored 683 runs. Over at Fangraphs this past week there was an article by Bradley Woodrum detailing this change in run environment and how it affects stolen base success rate. The most important part of the research is that each teams break-even point can be determined with the Nationals coming in at 69.38% while they had an actual success rate of 75%.
None of this is to say that north of 75% shouldn't still be the desired goal, but that 69.38% is a break even point, and when you're breaking even you're not gaining anything. What it does mean though is that the Nats have more room for error and should be more willing to run Span, Desmond, and Morse when the opportunity presents itself. With Morse's power gone the Nats break-even point is going to drop. Probably not by much as Harper, Zimmerman, and Werth should all hit more homers than they did in 2012, but on the flip side Desmond and LaRoche may hit less. Either way it looks like the Nats will be missing some power. Figuring though that a homer is four total bases and a steal is one, Span would have to successfully steal 48 bases to make up for the 12-homer drop from 2012 Morse to 162 game average Span.
48 steals without getting caught shouldn't be expected from Span, but combine 20 extra steals for the team total with Span's OBP at the lead-off position and his value as an offensive player starts to be understood. Span isn't going to be going into as many homerun trots as Morse, but he could still be trotting around the bases a good deal with Werth, Zimmerman, Harper, and LaRoche batting behind him. Then there is the other aspect of base running. For his career Span has taken the extra base (first to third on a single, first to home on a double) 48% of the time while Morse has done so 33% of the time and 28% in 2012.
What the change from Morse to Span in the Nats batting order loses in power it makes up for in OBP, stolen bases, and taking the extra base. In total the Nats had a lot of middle of the order type bats in Werth, Harper, Zimmerman, and LaRoche. Morse was a nice part of the batting order in 2012, but he wasn't what the Nats needed. The Nats needed someone at the top of the batting order who could get on base, run the bases, and get driven in by the middle of the order. Span is a different type of player from the rest of the Nats batting order, but that is exactly what they needed, and his presence is going to have a big impact on how many runs the Nats score in 2013.