On Tuesday, Fernando Rodney converted his 13th straight Save chance and 28th in 30 tries, while running his scoreless streak to 15 innings. Awaaay back on April 6, after the Rays-Yankees opener, some cynic wrote this:

– How many years can a reliever hang on while posting an ERA that starts with “4″? Rays’ winning pitcher Fernando Rodney has a 5-year streak going. Of the 318 active pitchers with 30+ games each of the last 5 years, Rodney is the only one who hasn’t had a single sub-4 ERA. Yet the Rays signed him for a guaranteed $2 million this year … and he set down the Yankees 1-2-3 in the 9th.

Rays fans have yet to thank me for the reverse-kibosh — Rays fans? Anyone? — but never mind that.

A major factor in Rodney’s out-of-the-blue brilliance is his dramatically improved control:

• 4.8 BB/9 for 2005-11;
• 1.4 BB/9 in 2012 (7 walks in 44.2 IP).

The 2 passes he issued Tuesday broke a streak of 15 games/16 IP without a walk — that’s half again as long as his best prior streak, and the 4th-longest this year for stints of at least 1 inning.

How rare is it for a reliever to have a year with a very low walk rate after many years with a high rate? Alas, targeting that particular question takes far too much work. So I’ll just take a quick peek at the career walk rates of the 56 relievers who have exactly 1 year with a BB/9 of 1.5 or less in 40+ IP, including this year.

(The point of “exactly 1 year” is to filter out those like Quiz and Eck with terrific career walk rates, and tilt the focus towards those for whom a very low season walk rate is not the norm. It’s not a perfect filter, but then, I don’t want to spend all day on this.)

The results are no surprise: Of those 56 pitchers, Rodney has the highest career walk rate, 4.52 BB/9 in 474 IP.

The other 55 guys in the study have career BB/9 ranging from 1.56 (Edward Mujica, 345 IP) to 4.12 (Mike Gonzalez, 376 IP). Gonzalez is also an outlier; the next-highest career BB/9 in this group are 3.32 (Dave Gumpert, 136 IP) and 3.29 (Rudy May, 2,622 IP). For the non-Rodney group, both the median and the combined average are 2.41 BB/9.

A slightly different sifting of this group: Rodney has 4 seasons of 40+ IP with a walk rate over 4, ranging from 4.3 to 6.7. Only two others in that group have even 3 seasons over 4.0 BB/9 (Gonzalez and Willie Hernandez); three have 2 such seasons, twelve have 1, and 38 have none.

So, yes, Rodney’s stark improvement in control is rare. But how is he doing it? That’s not really my field, but one or two things stand out in the splits:

• First-pitch strikes: Including balls put in play on the first pitch, Rodney has thrown a first-pitch strike to 63.0% of batters this year (102 of 162). His prior career rate was 56.7%. Not a huge difference, but even a modest change at the start can snowball through the at-bat. And once he gets ahead, he’s not slipping back. In past years, after an 0-1 count, Rodney went on to walk the man 6.0% of the time; this year, just 2.4% (1 of 41).
• Fighting back: After falling behind by 2 and 0, Rodney has unintentionally walked just 2 of 20 this year, 10%. His prior career rate was 35%. (Pitch stats through Monday, as B-R has not yet updated.)

I’m sure there are bigger factors that a wiser analyst could point out. Still, I wouldn’t be surprised if Rodney’s improved control boiled down to a spring training chat with Uncle Joe Maddon and/or pitching coach Jim Hickey, sending the message: Son, you’ve got good stuff. Just throw it over the plate, and if they hit it, why, our boys will run it down.

By the way, this is the third straight year that Tampa has installed a new closer age 30+, getting a terrific performance with much-improved control each time:

• Kyle Farnsworth, 1.9 BB/9 in 2011, less than half his prior rate of 3.9 and the best of his long career.
• Rafael Soriano, 2.0 BB/9 in 2010, prior career rate 2.8. Soriano had other years with the same control, but since departing for New York, his walk rate is up to 3.8.

Setup man Joaquin Benoit was also excellent in 2010, his first year with Tampa after many years elsewhere. His walk rate was 1.6 BB/9 in 2010, after 4.3 in his 4 prior years as a reliever. His walk rate has risen to 2.7 in 2 years since his departure.

It’s worth noting that Tampa Bay’s over-all walk rates in the last 5 years are not exceptional, with 3 seasons very near the AL average, and 2 in which they were good, but nearer to the average than to the best team. If there is an organizational philosophy about minimizing walks, the results have mostly been seen in the finishing relievers.