The decision came down to Towers or Jesse Litsch, one of the Blue Jays' top young pitchers. Towers, however, has a 5.36 ERA, nearly two runs higher than Litsch's 3.64 mark.
"He has pitched better," Gibbons said of Litsch.
Litsch will pitch Monday and Roy Halladay will throw on five days rest Tuesday.
Gibbons, however, wouldn't announce the corresponding roster move for Burnett, a decision they don't have to make until Sunday morning. Likely options include Jason Frasor or Brandon League.
Frasor has seen just six appearances since June 30 while League, hurt for most of the season, has posted a 6.75 ERA in seven games since he returned on July 15.
Overbay struggling: Lyle Overbay has batted just .241 (19-for-79) with no homers since he returned from the disabled list on July 12. The first baseman said he isn't feeling any pain from the hand injury that shelved him earlier this season.
"I am always in some kind of pain, but it is not affecting me," he said. "I am not trying to compensate to change my swing. It's one of those things where it hurts afterwards. I don't think about that when I am up there. I would like to blame it on that because I [stink], but that is not it. It is just trying to get in a spot to hit and I think I found that a little bit the last few days."
Overbay felt a change at the plate Wednesday against the Yankees, a game where he tied his season-high with three hits. It marked his first three-hit contest since July 16.
"I was thinking it was my hand and it was something else," he said. "It was reassuring. My weight was either too far back or too far forward. It wasn't where I wanted to be and I just kind of looked at some tape last year and went from there and tried to break it up a little.
"Hopefully I can continue on and it will come back in a little bit. I have a good feeling that I can keep that there."
Glaus slumping: Troy Glaus continues to see his average slide. In his last 20 games, Glaus is batting .108 (8-for-74) with one extra base hit. It's been even worse recently -- in his last 40 at-bats, he has just two hits.
Glaus' average has dipped all the way to .250, the lowest it has been since he went 1-for-4 on Opening Day. Gibbons said Glaus' large frame causes him to encounter slumps and isn't worried. Glaus started at third base and batted sixth on Friday night.
"He is due," Gibbons said. "He is a streaky hitter anyway. He is a long streak. Has a long swing -- he always has and he always will. When you are that size, you got to, there is no way around it."
Thomas red-hot: On the other hand, Frank Thomas has crushed the baseball in the past week. In Thomas' last six games, he is batting .480 (12-for-25) with two homers and 14 RBIs. Thomas entered Friday's game with a .265 average -- his best mark since May 3.
Gibbons believes nothing has changed for Thomas. A veteran and future Hall of Famer, Thomas will yield hot and cold runs every season.
"He is a power hitter and most of his career he has been a .300 hitter," Gibbons said. "Those guys go through that. The key for him is getting a good pitch to hit and putting a good swing on it. ... Just pick out the one he likes and turn it loose."
Pitching a plus: Led by Halladay and their young pitchers in Shaun Marcum, McGowan and Litsch, the Blue Jays have the American League's best second half ERA at 3.59.
"These guys have been there all year," Overbay said. "They have just been tremendous. We are just not getting the timely hitting. Everyone is starting to do their job and if they continue on doing that, we can make a run [for a playoff spot]."
Jays sign pick: Toronto agreed to terms with shortstop Kyle Gilligan, the team's 27th round selection in 2007 Draft. Gilligan, 19, played for the Toronto Maple Leafs of the Intercounty Baseball League and hit .283 with two homers and 12 RBIs. He was a member of the Canadian National Team in 2006 and attended Connor State Junior College in Oklahoma.
Bunts: Third base coach Brian Butterfield was one of several personnel that was fined in the Yankees and Blue Jays series. It was unclear what Butterfield was fined for, but Gibbons said Butterfield "had some words" for Yankees' first base coach Tony Pena ... The Blue Jays board had a message in large capital letters: Please Drink Plenty of Fluids. Toronto isn't used to playing in the KC heat -- heat that was 94 degrees with a 103 heat index at first pitch. Gibbons said it wasn't the hottest he had ever played in. For him, the warmest conditions were in Jackson, Miss. Starter Shaun Marcum, a Missouri State graduate and native of the Kansas City area, had several dozen family and friends at Friday's game.
Coming Up: Dustin McGowan (8-5, 4.11 ERA) and Leo Nunez (1-0, 1.93 ERA) will face off in the second game of the series Saturday night. First pitch is scheduled for 6:10 p.m. CT.
Conor Nicholl is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.