As Mariano Rivera walked to the mound June 19, a Yankee fan might have felt a pang of doubt. A combined 18 walks and hits had pockmarked his previous five and two-thirds innings over eight outings, more base runners, according to the Elias Sports Bureau, than Rivera had ever allowed over any other eight-game stretch in his major league career.

But on a late-spring afternoon in the twilight of a career, Rivera set down the Los Angeles Dodgers in order — flyout, strikeout, strikeout, the last against Yasiel Puig, the Cuban phenom born a few months after Rivera went pro 23 years ago. And in his three outings since, Rivera has allowed 2 of the 11 batters he has faced to reach base, resuming at age 43 his parsimonious ways, having allowed in his 19 big-league seasons one batter to reach base per inning.

Since his debut in 1995, Rivera has thrown 1,2482/3 innings and allowed a combined 1,253 walks and hits. His career WHIP — walks plus hits divided by innings pitched — is almost exactly 1.00.

How remarkable is that? Of the roughly 1,000 pitchers who have thrown at least 1,000 innings in a span going back nearly a hundred years, Rivera is the only one to keep batters off base at such a high rate. The average WHIP today, according to Elias, is 1.29, a full 29 percent higher.