Scott Rolen's Vanishing Walk Rate

Possessing a rare combination of patience, power and defense that belies his burly frame, the Reds' Scott Rolen has put together one of the most impressive careers of any third baseman in history. According to Baseball-Reference, Rolen ranks seventh all-time in Wins Above Replacement among those who played at least three-quarters of their games at the hot corner.

But, as good as Rolen has been for a decade and a half, his selection as an injury replacement for the 2011 MLB All-Star Game was more a commentary on the sad state of third base in the National League this season than a ringing endorsement of Rolen. The 36-year-old is turning in perhaps his worst offensive season in the majors, batting .241 with a .276 on-base percentage and a .398 slugging percentage. The most surprising aspect of Rolen's year is his nonexistent walk rate: he has drawn a free pass in just 3.5 percent of his plate appearances, compared to a career rate between 10 and 11 percent.

Rolen's lack of walks can be attributed to two factors: pitchers are throwing him more strikes, and he's chasing more often when they do decide to throw something located off the plate.

Last year, between 48-49 of the pitches that Rolen saw were located in the zone. That rate has increased this season to slightly more than 51 percent, which is well above the 48 percent average for non-pitchers. It's harder to work a walk when pitchers are challenging a batter more often.

And, on pitches that are thrown out of the zone, Rolen isn't showing as much patience.

Here's the league average swing rate on pitches located out of the zone:

 Now, here's Rolen's outside swing rate in 2010:

Rolen's swing rate on outside pitches, 2010

Rolen chased his share of high pitches, but he rarely offered at pitches off the corners or below the knees.

In 2011, however... 

Rolen's swing rate on outside pitches, 2011

He's still chasing lots of high pitches, but he's also going after more outside, inside and low pitches. His overall chase rate has increased from 24 percent last year to 30-31 percent in 2011. The league average for non-pitchers is about 28 percent. If the Reds are to stay in contention in the NL Central race, they'll need Rolen to start getting on base in addition to playing top-flight defense.