Much of the deliberation over whether or not Russell Martin deserves the two-year, $17.5 million contract he pulled in from the Pittsburgh Pirates yesterday will hinge on how his defense is viewed. Martin has been measured as a tremendous pitch framer, and for many that will be enough to put a notch in the team-friendly side for this contract.

But what about his arm Martin threw out just 24 percent of basestealers last season, down from 30 percent last year. The league rate also fell, from 28 percent to 25 percent — 2012 was the best year for basestealers since 2007, when they also accomplished a 75 percent success rate. Still, it was a disappointing year for the 29-year-old backstop, his first below average since 2008.

In today’s pitcher-friendly environment, the equation on the basepaths has shifted towards more and more stolen bases. Observe:

On a rate basis, there are now far more stolen base attempts (SBA) per stolen base opportunity (SBO, from Baseball-Reference: plate appearances through which a runner was on first or second with the next base open). The relationship is clear: the league took a year to catch up, but as run production goes down, stolen bases go up (For the record, the coefficient of determination between OPS and SBA/SBO is 0.78.).

It might seem counter-intuitive — the more run scoring drops, the more we hear about the sanctity of the out. Each of the 27 is hugely valuable, yes, but as run scoring drops each plate appearance is also more likely to produce an out.

The league on-base percentage has fallen from .336 in 2007 to .319 in 2012, and therefore the marginal out — the out risked by the stolen base — is less valuable. That’s why the “runCS” value in the Guts section — the cost in runs of a caught stealing — has lessened from minus-.433 in 2007 to minus-.398 in 2012.

Put another way, the stolen base becomes a less risky proposition because there is less to lose. The hitter at the plate is now less likely to get on base or hit a run-scoring extra base hit, and the chances of two hitters singling in an inning to knock a runner home drops in a compound fashion. Conversely, making the hitter’s job easier becomes more valuable now that the “wait for a three-run homer” strategy isn’t as viable.

The break-even rate on steals has fallen from 68 percent to 66 percent, down from 70 percent at the height of the steroids era in 2000. A player that stole 75 bases and was caught 25 times would have gained 4.2 runs of value in 2007. In 2012, that number rises to 5.1, and the player likely would have been running 10-20 percent more often; a routinely successful basestealer’s value in the running game therefore increases by some 30-40 percent.

The Pirates allowed 154 of 173 basestealers (89 percent) to successfully steal last season. The mark falls partly on the arms of Rod Barajas and Mike McKenry, but Pirates pitchers were also painfully slow to the plate. Opposing baserunners racked up over 23 runs of value against Pirates’ catchers; the average MLB team (27 percent caught stealing) would have given up just six runs.

The Pirates will still have A.J. Burnett, James McDonald and Wandy Rodriguez in the rotation as holdovers, and Jeff Karstens may be back as well. If Russell Martin really did get worse at throwing out baserunners in 2012, it’s an issue that could be exacerbated by the starting rotation’s problems with holding runners on. And in this brave new pitcher-dominated era, the attempts will be fast and furious, and each successful one allowed more costly.