McAllister is taking the spot which would have belonged to Fausto Carmona, before Carmona was shelved after injuring himself in Cincinnati on Saturday.
The right-handed McAllister was 8-3 in Columbus with a 2.97 ERA for the Clippers. He was acquired last year from the Yankees when Austin Kearns was sent to New York. McAllister was a third-round pick for the Yankees in 2006.
Toronto will send Carlos Villanueva to the mound. Villanueva has only appeared once against the Tribe, allowing two runs in two innings with no decision.
On the year, the Blue Jays' right-hander is 5-1 with a nice 3.24 ERA. In 72.1 innings, Villanueva has allowed only 56 hits, and has fanned 47 to go with 21 walks.
In his last appearance Villanueva got a no-decision in a 5-3 Toronto loss in Toronto, against Philadelphia. In that outing, Villanueva went 6.2 innings, allowing five hits and three runs, with four walks and three strikeouts.
Villanueva spent the first five years of his career in Milwaukee, where he went 20-24 for the Brewers in 230 games.
The Indians took two-of-three at the end of May/beginning of June in Toronto, and last year, swept the Blue Jays in a four-game series at Progressive File in late June/early July.
Jose Bautista leads Toronto in all three major offensive categories, with a .335 batting average, 28 homers and 60 RBI. As a team the Blue Jays are tied for 15th in baseball with a .254 average but are third in homers with 102.
The Indians are hitting .249 as a team and are led by Travis Hafner, at .338. Asdrubal Cabrera leads in homers with 14 -- one more than Carlos Santana -- and in RBI with 49.
Toronto comes in to this series in fourth place in the AL East at 42-46, 10.5 games behind the Yankees. Toronto has lost two straight and seven of their last ten.
After Thursday's game, night games will follow on Friday and Saturday, before a 1:05 game on Sunday that will be the last game before the All-Star break.