Diamondbacks get three runs off Jansen, two in 15th for double comeback win

At first, the drama played out beyond the field. The display for the radar gun at Chase Field resides on a screen in the right-field seats, above an advertisement for a bar and below the plaques commemorating the two retired numbers in Arizona Diamondbacks history. On Monday evening, as the Dodgers protected a three-run lead, the pixelated digits carried more weight than usual.

The gun tracked the speed of Kenley Jansen's cut fastball: 90 mph . . . 88 mph . . . 89 . . . 92 . . . 91. A pitcher of Jansen's pedigree rarely receives such scrutiny. But those were the consequences after his first outing of the season, in which his velocity averaged 89.6 mph and he shrugged off questions in search…