Putting The Greatness Of Yankee Hall Of Fame Closer Mariano Rivera In Perspective

In recent weeks in this space, we’ve been taking a look at the current group of MLB closers. This piece summarizes their 2019 performance, with supporting data for AL and NL closers. This one covers their difficulties in lasting long enough to earn long, lucrative free agent contracts. Two other pieces feature Edwin Diaz, who was better than he appeared in 2019, and Alex Colome, who wasn’t as good as his numbers suggested. This one surveyed the current crop of MLB closers and identified the best bets for long-term on-field and financial success.

Some of the main themes of the above articles were hammered home again and again:

• Closers as a group are darned good, better at missing bats, minimizing walks and managing contact than all but inner-circle elite starters
• Their stars often burn out brightly, before they can reap the financial benefits of their excellence in free agency

The rules don’t necessarily apply to Mariano Rivera, the greatest relief pitcher in the history of the game, and arguably the greatest pitcher – period – on a per inning basis.

Let’s look at Rivera’s performance in those three key areas: bat-missing, walk minimization and contact management.

In 2019, a much more whiff-happy environment than the one Rivera pitched in during his career, the average AL and NL closer had sky-high whiff rates of 31.9% and 32.7%, respectively. 17 of the 30 primary closers had whiff rates of over two full standard deviations higher than the league average of all pitchers.

Rivera had a 30% K rate in only one individual season (1996), and in only three seasons (1996, 2008, 2009) did he post a K rate over two standard deviations higher than league average. He got his share of whiffs, but that wasn’t the central focus of his game. Many other closers in his era struck out hitters at a higher rate.

Rivera was at the elite level in minimizing bases on balls. Beginning in 2001, he only exceeded a 6.0% walk rate – which is typically at least a full standard deviation lower than league average – in two of his remaining 12 injury-free seasons. In 9 of those 12 remaining seasons, his walk rate was below 5%, which is typically right on the fringe of being two standard deviations better than league average.

As a frame of reference, consider that 2019 AL and NL primary closers posted average walk rates of 8.6% and 7.6%, respectively, with only three closers posting marks below 5.0%. Rivera never once a posted a walk rate of 8.6% or higher in a season.

On at bats where the ball was not put in play, Rivera was really good. You may have seen me reference the concept of the K/BB Multiplier in this space. Based on a pitcher’s K and BB rates, you can estimate his “Tru” ERA- (my metric that incorporates exit speed/launch angle into pitcher performance measurement) by multiplying his Adjusted Contact Score (more on that in a minute) by his K/BB Multiplier.

Pitchers with better than average K and BB rates have lower multipliers (100 = average). Rivera’s career multiplier (excluding his 1995 rookie season as a starter) is 83.7. That’s really good, but not elite. Max Scherzer’s is 77.0. Chris Sale’s is 75.9. Mike Mussina (84.1) is an excellent comp for Rivera’s K/BB ability, abetted by the fact that their careers overlapped significantly.

Let’s talk about contact management, and the concepts of Unadjusted and Adjusted Contact Score. Unadjusted Contact Score measures the actual production allowed by a pitcher on balls in play, relative to 100, the lower the number the better. Adjusted Contact Score is the production a pitcher “should have” allowed on balls in play based on their individual exit speeds/launch angles.

In a given year, a pitcher’s Unadjusted and Adjusted Contact Scores might diverge significantly for any number of reasons, including ball park, team defense, and of course, random chance. Over a career, however, these factors in most circumstances tend to even out.

Since 2013, when I last updated my Adjusted Contact Score metric and applied it to all ERA-qualifying starting pitchers, only four pitchers have qualified in all seven seasons. Three of them, Scherzer (94 vs. 94), Jon Lester (99 vs. 99) and Rick Porcello (105 vs. 105), have posted matching average Unadjusted and Adjusted Contact Scores. The fourth, Julio Teheran (90 vs. 102) regularly posted better unadjusted marks due to a pitcher-friendly home park and strong team defense.

Bottom line, we can look at Rivera’s Unadjusted Contact Scores to get a good feel for his true contact management ability. Rivera’s CAREER Unadjusted Contact Score (again, excluding 1995) is 63.0. In any given year, the Contact Managers Of the Year in each league post marks in the 75-80 range. The four best active contact managers among starters with at least four qualifying seasons from 2013 onward are Jacob deGrom (81 Average Adjusted Contact Score), Clayton Kershaw (84), Dallas Keuchel (85) and Kyle Hendricks (85). No starter ever has posted a career average (qualifying seasons only) unadjusted or adjusted mark under 80.

Rivera’s CAREER AVERAGE unadjusted mark is 63.

He never once posted a single-season Unadjusted Contact Score higher than 96.

Only twice in 17 injury-free seasons did he post an Unadjusted Contact Score greater than or equal to 80.

Only two 2019 closers posted Unadjusted Contact Scores lower than Rivera’s career average of 63 – and both were flukes. Brandon Workman (32 vs. 71) and Alex Colome (57 vs. 116) both posted much higher adjusted marks. The best Unadjusted Contact Score posted by a 2019 closer was Jose LeClerc’s 66.

Rivera posted Unadjusted Contact Scores of better than 63 in 10 individual seasons.

Now let’s quickly pivot back to the K/BB Multiplier. Multiply his 63 career average Unadjusted Contact Score by .837, and it gives you a career “Tru” ERA- of 53, a little below his ERA- of 49 and quite a bit better than his Fangraphs’ FIP- of 62.

Mariano Rivera threw a cut fastball almost every pitch throughout the vast majority of his career. Everyone knew what was coming but there was little they could do about it. They might put it in play, but it would almost always be hit on the ground weakly. He defied all of the rules that apply to most closers because of his ability to repeat pitch execution and location at will for two decades. Those of us who got a chance to see him work were fortunate.