The 31-year-old is a perfect 6-for-6 in save opportunities this season, but that doesn't mean that everything has gone as planned, physically.
"There are days when it just doesn't feel good," said Janssen, whose collarbone was shaved down during the offseason. "You can't always play catch like you want to, or get loose as fast as you want to, but nothing that's going to set me back or re-injure [the shoulder].
"It's more if I could get a couple of ticks more on my velocity, if I could warm up a little bit ... I wouldn't say quicker, but more crisp, so it doesn't take as long to warm up."
Janssen has experienced a noticeable drop in velocity through the first three weeks of the season. His four-seam fastball and sinker have averaged 90 mph, according to Brooks Baseball, compared with 92 mph for both pitches last season.
But the drop has had no impact whatsoever on his early results. He has allowed just one run on three hits while striking out 11 in eight innings. Of his six saves, all but one have come as part of a three-up-three-down inning.
Despite the success, Janssen's tone during a meeting with reporters was somewhat downcast. He conceded that there were times this year he was forced to inform manager John Gibbons that he simply didn't feel well enough to go on that particular day.
Once he takes the mound, though, he has done whatever he can to put the injury woes and lengthy rehab behind him.
"I'm not thinking about it," he said. "Whatever you have that day is what you have, and you've got to pitch with what you've got. To look at the miles per hour is deflating enough, so I've stopped doing that. You've just got to pitch, and you read swings, you read the hitters' reactions and make pitches with your offspeed pitches.
"I don't know if I can be better, but I know my arm can feel better. You don't want to look too far into everything, because I've been good enough, but I'd like to say my arm can feel better."