The shirts read #RaiseTheBar and VoteDelabar.
Fans can vote on mlb.com for the final player on each of the American League and National League all-star rosters for the July 16 game in New York at the home of the Mets.
Delabar's AL rivals in the vote are also pitchers: David Robertson of the Yankees, Boston's Koji Uehara, Texas' Tanner Scheppers and Detroit's Joaquin Benoit.
The National League vote is probably more clearcut with Washington shortstop Ian Desmond, first basemen Freddie Freeman of Atlanta and Adrian Gonzalez of Los Angeles, and San Diego outfielder Hunter Pence up against Dodgers outfield sensation Yasiel Puig.
"To be considered is an honour," said Delabar, wearing one of the new T-shirts. "There's a lot of guys out there that could be in consideration for the final vote."
The Jays are partnering with the Atlanta Braves, asking their fans to fill the lineup holes by voting for Delabar and Freeman.
Should Delabar win, the hard-throwing reliever will join teammates Jose Bautista, Edwin Encarnacion and fellow pitcher Brett Cecil. Jays manager John Gibbons will also be there, as a coach for the AL squad.
The Kentucky native, who will turn 30 the day after the all-star game, went into Sunday's game against Minnesota with 57 strikeouts (tied for the league lead among AL relievers) in 40 innings and a 5-1 record.
Delabar had not surrendered more than two runs in any of his 35 appearances and had given up just four earned runs in his last 31.1 innings pitched.
Delabar's journey to the majors has been a hard road.
He had Tommy John surgery in 2002 and has baseball stitches tattooed over the scar on his right arm. A plate and nine screws hold his elbow together from a 2009 operation.
Doctors used the plate and screws to repair the elbow on Sept. 29, 2009, after the six-foot-five reliever fractured his elbow pitching for the Brockton (Mass.) Rox of the Canadian-American Association. Released by the San Diego Padres the previous year, after five undistinguished years, he had never got above Class-A ball.
After the surgery, Delabar returned to Kentucky where he worked as a substitute teacher and helped coach a high school baseball team. He didn't pitch in 2010, although he did play outfield on a softball team.
Delabar was working at the Players Dugout in Elizabethtown, Ky., a facility aimed at developing baseball and softball players when owner Joe Newton told him about a new system called Project Velocity which has players work out with balls of various weights and also going through the throwing motion without releasing the ball.
The program strengthens the shoulder while making the arm quicker at the same time.
Delabar asked if he could give it a shot so he could teach it to his baseball players. As he worked his way through the program, he saw his pitching speed was increasing. So he started focusing on a comeback.
Before the broken elbow, Delabar's arm topped out at 94 m.p.h. — once in 2006. Consistently he threw from 87 to 92-93 m.p.h. At spring training, he estimated his low at 92 and high at 97-98.
The Mariners signed him and sent him to Class-A in 2011. He worked his way up through the minors and made his major league debut Sept. 11, 2011, against the Kansas City Royals.
He was traded to Toronto in July 2012 in exchange for outfielder Eric Thames. He finished the season with a 4-3 record with a 3.82 ERA, striking out 92 and walking 26 in 66 innings.
"It's been a long journey," said Delabar.
The pitcher said he would have laughed if someone had told him three years ago that he would be in consideration for baseball's all-star game.
"You kind of just go day by day. And just work hard for the future and just hope that all things play out. You never expect something like this to happen."
Thanks to Delabar, Cecil is also on the Velocity Program which is tailored to each athlete.
"It's a proud moment," Delabar said of seeing Cecil's success after the program.