The Blue Jays gave the Rangers cash for Mench, who was with Triple-A Oklahoma after failing to make the club as a non-roster invitee in spring training. Mench was hitting .282 with three home runs and 18 RBIs in 29 games for Oklahoma.
"I'm working on three hours sleep," Mench said before the start of a four-game series against the Indians. "It's been a whirlwind last 24 hours."
He was in Oklahoma City and got the called with the news of the deal at 3 a.m.
He is now a teammate of Toronto right-hander Roy Halladay, who he hit with a line drive on July 8, 2005. Halladay, 12-4 with an AL-leading 2.41 ERA at the time, missed the rest of the season with a broken left tibia.
"We've talked about it," Mench said.
Mench was drafted by the Rangers in 1999 and hit at least 25 home runs in consecutive seasons in 2004-05 before getting traded to Milwaukee in a deadline deal for Carlos Lee in 2006. Earlier that year, he became the fifth player in major league history to homer in seven consecutive games.
The Rangers already had a crowded outfield before Brandon Boggs was brought up from Oklahoma and hit .343 in his first 10 games.
Wilkerson was released by the Seattle Mariners on April 30.
Mench was in Toronto's lineup as the designated hitter and Wilkerson started in left field Friday night.
"They are two guys we've always liked," Blue Jays manager John Gibbons said. "We've been looking for a right-handed bat to complement [Matt] Stairs at DH. We've also been looking for a left-handed hitter. To be able to get both is like a bonus."
The 30-year-old Wilkerson played 19 games for Seattle and hit .232 with four doubles and 10 walks in 56 at-bats. He went 3-for-3 with a walk in his last game for the Mariners on April 29 in Cleveland, being designated for assignment after the game.
In 887 career games, Wilkerson has a .249 average with 118 home runs and 376 RBIs.
To make room on its 25-man roster, Toronto optioned infielder Joe Inglett to Triple-A Syracuse. To clear space on their 40-man roster, infielder Sergio Santos and left-hander Gustavo Chacin were designated for assignment.
In 13 games with the Blue Jays this year, Inglett batted .303 (13-for-33) with four RBIs.
Chacin, who went 25-15 in 58 starts over the past four seasons for Toronto, was 0-4 with a 7.00 ERA with Class A Dunedin of the Florida State League this year.
Santos hit .193 (17-for-93) with four RBIs in 26 games at Triple-A Syracuse this season.