It's because the Blue Jays are playing a series at Comerica Park.
"I've had this marked on the calendar, coming to Detroit here, since I first got the job," he said. "I was really looking forward to this week, as well as the All-Star break in July."
Joe Siddall played briefly for the Detroit Tigers, and spent a couple of years on their coaching staff after he retired.
He got the Jays announcing job right before the current season started.
"This is very conflicting. I've been a Tiger fan since I was a little boy. Our whole family is really Tiger fans," he said. "Getting this new job has changed things a little bit, and we've kind of got some people on the Blue Jay bandwagon right now in my family."
Now, Siddall is on the road again for the summer.
"The giggest adjustment is being away from home again. It's kinda like being a player all over again," he said. "That part of it's no fun, but we're trying to have as much fun with it as we can as a family, and having my kids and my wife come and see me in Toronto."
Siddall can be heard on Sportsnet's TV broadcasts this week, although he normally does radio work.
Toronto won the first game in the series Tuesday night, 5 to 3.