Actually, by starting Strasburg OD, he may be the only starter to get an extra day's rest the first 3 times through the rotation. As Loshjott pointed out, they only have 4/6 as a scheduled off day until 4/22. 16 in a row from 4/7 to 4/21. They can go with 5 starters from the get go. Stras will likely go on 4/11 rather than 4/10 to get the extra day. No other starter is lined up for an off day until Gio on 4/22. Gio can go 4/23 and 28, JZ 4/24 and 29, then there is an off day.
What I'd like to see perhaps is a spot start by Detwiler or (Lannan /Wang) on 4/16. This would give the rotation an extra day and push Stras to 4/23. This would mean he goes 4/5, 4/11, 4/17, and 4/23 the first 4 times through the rotation, or effectively treat him like he's in a 6 man rotation while the rest of the staff stays on a normal 5 man rotation.
Knowing Davey, he's figured this out.