So I've heard a lot about Starters

I’m used as a reliever for the most part even though at the beginning of the season I was told that I have a chance for the rotation. I am trying to work in workouts during the season but it’s hard to know when to work out since I’m never sure when I’m going to pitch next. It could be the next day or the next week. I want to get some strength training in there such as preacher curls and what not, but I’m afraid to do that since I could be pitching the next day. Any suggestions?