The scary thought to Borzello is that Jansen's cutter has the potential to be even more dominant than it's been in the last month or so. Jansen has struck out 23 of the last 36 batters he's faced and is averaging 15.87 strikeouts per nine innings -- tops in the Majors among those with at least 45 innings pitched.
"It can only get better, and it has gotten better throughout the year," Borzello said Wednesday. "Now he's putting the ball where he wants and just attacking hitters like last night. It's unbelievable."
Jansen said Tuesday's hold was the most fun he's had all season. He came in with one out and coolly stranded two runners with a pair of routine strikeouts to preserve Clayton Kershaw's 20th win.
The goal for Jansen now is to better understand the cutter so he can locate it. He said he still hasn't completely gotten a feel for just how much the ball will cut or where it will end up when he throws it, though he's getting there.
"It's a natural fastball and it cuts a lot, so I know I have a cutter now," Jansen said. "The key is learning right now how to start it."
Borzello remembered Rivera learning the same way. Suddenly his ball started cutting and the Panamanian righty made a career out of the pitch. Jansen didn't know he had a cutter either until Borzello informed him during a bullpen session that his fastball had late movement on it.
Borzello said Jansen will eventually get to the same level of control as Rivera. But for now, the variance in where his cutter will finish and how much it will move is one of the biggest reasons he has kept hitters off balance.
"I just throw, try to be ahead all the time," said Jansen. "That's how how my thinking is. Stay ahead, and when I have it 0-2, two strikes, that's the time I really want to put them away with a strikeout."
Multiple times this season, stunned opposing hitters have turned to catcher A.J. Ellis after striking out and asked him just what pitch Jansen was throwing.
"It's hard to square up because it never ends up where you think it's gonna be," Ellis said. "You don't see guys throw that hard with that late movement."