Loup took the loss in the Blue Jays' second game of the 2015 season.
Entering with a 3–1 lead against the New York Yankees in the eighth inning, he loaded the bases without recording an out.
All three runners would come in to score and Toronto would lose, 4–3.
Loup experienced ineffectiveness throughout the season, posting an ERA over 5.00 into August.
Following a 3–1 win over the Yankees on August 16, Loup was optioned to the Triple-A Buffalo Bisons.
He was recalled on September 1.
For the season, he was 2-5 and had a 4.46 ERA.

On January 15, 2016, Loup and the Blue Jays avoided salary arbitration by agreeing to a one-year, $1.05 million contract.
Loup began the 2016 season on the disabled list with a left forearm flexor strain.
He began a rehab assignment with the Dunedin Blue Jays on May 14.
On May 21, he was moved up to the Buffalo Bisons to continue rehabbing the injury.
Loup was recalled on August 21.
On August 27, Loup was placed on optional waivers.
He accepted a minor league assignment the following day.
For the season, he had a 5.02 ERA.

On January 13, 2017, Loup agreed to a one-year, $1.125 million contract for the 2017 season.
He finished the season with a 2–3 record and a 3.75 ERA in 70 games, while giving up a career-high 4.5 walks per nine innings.

On January 12, 2018, Loup signed a one-year, $1.8125 million contract.
For the 2018 season, Loup logged ​35 ²⁄₃ innings for the Blue Jays in 50 appearances, with a 4.54 ERA, while giving up a career-high 11.1 hits per nine innings, before being traded to Philadelphia.
Loup took the loss in the Blue Jays' second game of the 2015 season. Entering with a 3–1 lead against the New York Yankees in the eighth inning, he loaded the bases without recording an out. All three runners would come in to score and Toronto would lose, 4–3. Loup experienced ineffectiveness throughout the season, posting an ERA over 5.00 into August. Following a 3–1 win over the Yankees on August 16, Loup was optioned to the Triple-A Buffalo Bisons. He was recalled on September 1. For the season, he was 2-5 and had a 4.46 ERA.
On January 15, 2016, Loup and the Blue Jays avoided salary arbitration by agreeing to a one-year, $1.05 million contract. Loup began the 2016 season on the disabled list with a left forearm flexor strain. He began a rehab assignment with the Dunedin Blue Jays on May 14. On May 21, he was moved up to the Buffalo Bisons to continue rehabbing the injury. Loup was recalled on August 21. On August 27, Loup was placed on optional waivers. He accepted a minor league assignment the following day. For the season, he had a 5.02 ERA.
On January 13, 2017, Loup agreed to a one-year, $1.125 million contract for the 2017 season. He finished the season with a 2–3 record and a 3.75 ERA in 70 games, while giving up a career-high 4.5 walks per nine innings. 
On January 12, 2018, Loup signed a one-year, $1.8125 million contract. For the 2018 season, Loup logged ​35 ²⁄₃ innings for the Blue Jays in 50 appearances, with a 4.54 ERA, while giving up a career-high 11.1 hits per nine innings, before being traded to Philadelphia.
Aaron Loup