Replacing a legend is never easy... just ask Tino Martinez or whoever plays shortstop for the Yankees next season. Heck, even Mickey Mantle was booed when he took over for Joe DiMaggio in center field in 1951.
During spring training, David Robertson admitted that he was not replacing Mariano Rivera: “You can't replace legends. Somebody like Mo, you may never see again the game of baseball... But he's gone now. Someone has got to take over that role... It's just that I will never be Mo. I hope people can understand that.”
Robertson is correct in that he'll never be Mo, but he is doing his best impersonation of him this season.
And yet the biggest storyline here might be that there is no story. Robertson is dominating the ninth inning and somehow has flown under the radar as one of best closers this season.
Let's take a few minutes now to appreciate the underrated awesomeness of D-Rob in 2014.
Strikeout Machine His strikeout numbers this season are straight out of a video game. Robertson is averaging 15.6 strikeouts per nine innings, and has struck out 43 percent of batters faced this season. Both of those marks would easily be franchise records and are second only to Aroldis Chapman in 2014 among pitchers with at least 30 innings.
Robertson has gotten 103 outs this season and more than half – 60 – have been via strike three. He's been even more dominant when limiting it to just save situations. Two out of every three outs he gets in a save opportunity are strikeouts. Let that sink in for a moment.
When he isn't striking out batters he's usually generating weak contact, with a groundball rate of 50 percent. That mix of strikeouts and grounders is literally unprecendented in recent baseball history.
Fangraphs.com has batted ball data going back to 2002. Since then, no pitcher with at least 30 innings has finished a season with a strikeout rate of at least 40 percent and a groundball rate of at least 50 percent. Not one.
Clutch D-Rob Robertson doesn't throw perfect innings as often as Rivera did, but it's hard to argue he isn't as amazing in clutch situations.
He has faced nine batters with a man on third base this season. None have gotten a hit. Overall, opponents are hitting .147 (5-for-34) with runners in scoring position this season, a mark that Rivera reached only once for a full season (2004).
You could also easily make an argument that no pitcher in baseball has been put into more clutch situations than Robertson this season.
Leverage Index is a statistic that attempts to quantify the pressure of individual at-bats based on the score, inning, outs and baserunners. A Leverage Index of 1.0 is neutral; anything above it is considered “higher pressure” and vice versa.
Robertson's average Leverage Index this season when entering a game is 2.17, the highest in baseball (min. 30 IP).
Robertson has also been at his best when facing the best teams. He has allowed only one earned run in 21 innings (0.43 ERA) and is 15-for-15 in save opportunities against teams with a winning record.
The Luck Factor Perhaps the most amazing fact is that he has done all of this despite being “unlucky” this season. His batting average on balls in play is .338, the highest rate of his career and well above the Yankees average of .305.
Both of his ERA estimators (FIP and xFIP) indicate he should have an ERA that is roughly a run below his actual ERA, which was inflated by his lone disaster outing on June 1 when he gave up five runs against the Twins.
So while we sit back and enjoy the amazing job that Robertson has done this season in replacing the irreplaceable, you can also appreciate the fact that he should be on track for an even better performance after the break if his luck evens out.