Santos, who was the Blue Jays' biggest offseason acquisition and their closer of the future, hasn't pitched since April 20, but the Blue Jays have gotten adequate production from Janssen during Santos' absence.
Entering Wednesday's contest against the Royals, Janssen was 10-for-10 in save opportunities since taking over the role. In those 10 save situations, Janssen has allowed just three baserunners in 9 2/3 innings pitched.
"He hasn't changed who he is as a pitcher, whether he is pitching the eighth or ninth inning," Blue Jays manager John Farrell said. "In some ways, he has become even more efficient in the ninth."
Janssen started the year as Toronto's setup man, and after a trial run with Francisco Cordero as the closer, the Blue Jays made the switch to Janssen on May 9.
"He has been able to expand the zone by design and get some [players to] chase up," Farrell said. "He has been efficient, aggressive in the strike zone and, actually, he has got a lot more swing and misses in the ninth inning."
Janssen sports a 2.56 ERA and 0.88 WHIP to go along with 32 strikeouts in 31 2/3 innings. The 30-year-old is coming off his best month of the season in June, when he held opponents to a .167 average to go along with a minuscule 0.90 ERA.