The 30-year-old has remained healthy after appearing in just 11 games during his first year and a half with the club following of a series of arm injuries.
"The way I'm feeling, the way I'm bouncing back after I throw, this is the best I've felt and I'm just fortunate things are going my way right now," Santos said.
In 27 games out of the bullpen this season, Santos has allowed just four earned runs in 23 innings while limiting the opposition to a .120 average (9-for-75). He has stranded all but one his 19 inherited runners.
When Santos returned at the beginning of August following surgery on his right elbow, it wasn't immediately clear how he would fit into the club's bullpen. Right-hander Casey Janssen was firmly entrenched as the Blue Jays' closer, while Steve Delabar and Brett Cecil settled into their roles as setup men.
Santos was used in middle relief and occasionally had to be throw more than one inning at a time upon his return. It was essentially a mop-up role, but since then, he has gained the trust of manager John Gibbons.
Santos is now being used as one of the primary setup men for Janssen. He alternates the opportunities with Delabar while averaging a strikeout per inning and further solidifying what was already an impressive relief corps.
"That was a big motivating factor to me coming back," Santos said of proving his doubters wrong. "I wanted to prove to myself and everybody else that I still have the ability to get people out.
"That's what I was working hard for, that's what the light at the end of the tunnel was when I was down in Dunedin rehabbing and almost losing my mind. It's just pushing myself and knowing that when I did get an opportunity again, to try and make the most of it."
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.