MLB catcher becomes 1st player in league history to play for both teams in the same game

Jansen made Major League history by being the first player to play for both teams in the same game. Initially with the Blue Jays, he was at bat during a game against the Red Sox that was delayed and rescheduled. After being traded to the Red Sox, Jansen played against his former team, marking a unique achievement in baseball history.

What team did Jansen play for before being traded to the Red Sox?

What was the reason for the delay in the June 26th matchup?