ESPN - Agent wants players' union to investigate Twins' call-up snub of Liriano - MLB
I don't think they have much of a case, a team has every right to promote/demote players as they want and when your record and ERA is 0-3 and 11.32 at the start of the season that's enough "evidence" to say they had the right to make sure he was good and ready before he's called up. I'm guessing they want to try to trade Livan before calling him up so you can't really pull him from the rotation until he's traded.
I don't think they have much of a case, a team has every right to promote/demote players as they want and when your record and ERA is 0-3 and 11.32 at the start of the season that's enough "evidence" to say they had the right to make sure he was good and ready before he's called up. I'm guessing they want to try to trade Livan before calling him up so you can't really pull him from the rotation until he's traded.