QUOTE (daggins @ Apr 5, 2014 -> 10:43 PM)
This makes it pretty explicit:
"Davidson is in a bit of a similar position. Thanks to those almost two months in the majors last season with the Diamondbacks, he's got 50 days of service. If he is on the Opening Day roster, and remains on it the whole season, he'll have accrued well over a year of service time and be on track to be a free agent after the 2019 season. But, if instead the White Sox have him "work on some things" at Charlotte until 61 days have passed, he won't and the White Sox will control him until through 2020."
From the SSS article about service time.
61 days is right around June 1st.
That's not exactly how it works any more, it's difficult to impossible to project how many days it will require to be a free agent in 2020 at this point because the super-2 deadline is based on the numbers for all guys who are called up and qualify.