Both relievers were promoted from Triple-A Las Vegas after Toronto's relief corps were required to pitch 13 2/3 innings during the past two days against the Rangers.
Utility man Yan Gomes was optioned to Las Vegas while Japanese right-hander Ryota Igarashi was designated for assignment to make room on both the 25- and 40-man rosters.
"Given the number of innings and pitches thrown by our bullpen the last two days, we needed to get two fresh arms in here," Blue Jays manager John Farrell said.
"Francisco Cordero would be our closer today and Luis Perez is available, but every other regular reliever we have needs at least one, if not two, days off in some cases."
Chavez helped stop the bleeding in Sunday's 12-6 loss, picking up the slack after Kyle Drabek was knocked out after three innings. Chavez allowed three runs and struck out seven -- including five in a row at one point -- in five strong innings as the Blue Jays were able to save the rest of the bullpen.
Chavez was originally scheduled to start for the 51s on Sunday afternoon but instead took a late-night flight from Salt Lake City, where his team was playing a road series. The 28-year-old entered Sunday 6-10 with a 5.36 ERA in parts of four seasons in the Major Leagues.
The native of California started making a name for himself in the Blue Jays' organization during Spring Training. A strong performance in camp garnered a lot of attention and he was a finalist for the No. 5 spot in the rotation, which was eventually handed to top prospect Drew Hutchison in April.
Chavez started the year in Las Vegas, where he went 6-2 with a 3.72 ERA in 10 starts.
"Just being able to repeat my mechanics," Chavez said when pointing out the key to his success this season. "Years past, I've been changed a lot as far as mechanically. This year they just let me go out and pitch and probably because I was able to repeat my mechanics. That's the one thing you need in this game to be consistent at all."
Beck, 27, made his Major League debut with the Blue Jays last season. He was 1-0 with a 1.31 ERA while striking out 13 in 20 2/3 innings with Las Vegas this season.
Toronto's decision to option Gomes back to the Minor Leagues wasn't easy. Gomes had become a favorite of Farrell's and proved valuable with the ability to play first, third and catcher while also taking pregame work in left field.
Gomes hit .227 (5-for-22) with two home runs and five RBIs in eight games.
"It was difficult," Farrell said. "The two optionable players that recently joined us are both Yan and David [Cooper]. The fact is Cooper's left-handed bat gives us a little bit more balance. Yan was understanding of the situation, albeit disappointed but we were in a situation where we needed to make some roster moves to get fresh arms in here."