Is Mariano Rivera actually struggling?

Today I read an article on ESPN by Howard Bryant suggesting that Mariano Rivera is in decline and it’s easy to see why he would believe this.

Mariano Rivera is 39 years old. He’s coming off of shoulder surgery. His ERA this season is a full run higher than his career mark, and almost 2 runs higher than last season. He’s already given up more home runs than he has in any season since 2001.

But Mariano Rivera is not in decline. In fact, over the past few seasons and into this season, he has been pitching far better than at any point in his career.

Let’s just take a look at what he’s done so far this season. While he has given up too many homeruns that can be explained away by equal parts bad luck and the new Yankee Stadium. His HR/FB rate, a number that should be somewhere near 10/11%, is hovering around 25%. About a quarter of all flyballs Mariano Rivera has allowed have gone for homeruns. If we assume this number should be around 10/11%, and it should, we can assume Rivera should have given up about 2 or 3 homeruns, not 5. Still higher than usually, but hovering around or bellow a homerun per inning is not horrible at all.

Rivera still keeps the ball on the ground at an average to above average pace, although he has struggled just a bit with that this season. His GB% of 45.1% is right around the league average, and considering it’s in such a small sample size (batters have put just 71 balls into play against him) we can assume that it is in his normal range.

Let’s look at how well he is missing bats right now. So far this season, he has a strikeout rate of 10.66 per nine innings, which is the highest level he has posted since 1996 when he was a 26 year old star middle reliever, similar to Joba Chamerlian over the past couple of seasons. While there has been a noticeable drop in velocity, and batters are making more contact of his pitches in general, Rivera is still striking out more guys than ever.

The biggest indication that Rivera is not “done” is his fantastic control. So far in 25 1/3 innings, Rivera has walked 2 batters. And one of those walks was intentional, order by the manager, and apposed by Rivera. If Girardi had not forced Rivera to walk an injured Evan Longoria, a move widely questioned at the time, Rivera would currently have a 30/1 K/BB ratio. Even with that intentional walk, Rivera has a 30/2 K/BB rate, by far the best in baseball (second place is Toronto’s Scott Downs with 25 Ks to 4 BBs).

While he does have an ERA over 3 for the first time in a while (hey, a 3.2 ERA is still good) and he has been hit harder than usually, Rivera is combining his great stuff and amazing control to put together one of his finest seasons ever, despite his age, injuries, and loss of velocity. Expect this to continue until Rivera shows a sign of slowing down.