Last season, it was a right shoulder injury that limited him to just six games, while his 2013 campaign was derailed until the All-Star Break because of bone spurs in his right elbow. That created plenty of doubt about whether Santos would be able to remain on the field, but a month of good health is starting to alter his outlook.
"My main thing is to be around and to stay healthy, and I feel like pitching the way I have the last month, it's kind of put me in a good position to build off for next year," Santos said. "Finishing off this year was really important to me just to prove to myself that I am healthy, I can stay healthy and I can repeat my delivery consistently."
Santos hasn't had much of an opportunity to showcase his skills in a Blue Jays' uniform, but since returning to the Major Leagues at the beginning of August, his powerful arm has been on full display. Entering Friday, he had posted a 2.13 ERA with just six hits and 10 strikeouts over 12 2/3 innings.
Perhaps the most impressive aspect of Santos' return to the mound has been his control. Even when he was a closer in Chicago, Santos walked more than four batters per nine innings, but since being activated from the 60-day disabled list, he has walked just three.
It's an encouraging sign for a pitcher who needed to silence the critics and also eliminate his internal doubts about being able to stay healthy. With Casey Janssen firmly entrenched as Toronto's closer, Santos will remain in middle relief for the immediate future, but could be ready for a greater role if there's an injury or trade before the start of next year.
"Just like everybody wants to be an ace of the staff, everybody wants to be a three-four hitter. When you're a reliever, you want to be the guy when the game's on the line to be on the mound," Santos said.
"Right now, my main goal is just to go pitch-by-pitch. I know it's cliche and old, but the more I focus on that, the more I feel like everything else will take care of itself. If I continue to put up zeroes, I feel like good things are in store for me."
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.