I think, based upon last year, as Mick is getting up there in age, he will be performing every couple of shows, or make an appearance half way through select shows per month. That seemed to be the trend last year as he was recovering from his heart issue. Personally, if I were going to the show, a part of me says that I would like to know if he is going to be there (I would go regardless as I love Foreigner, but Mick just brings something so special), however a part of me also wouldn't want to know because I like surprises. I would love to hear in between songs Kelly introduce Mick, and then the whole dang HOUSE comes down, or Mick just magically walks onto the stage with his guitar and starts wailing! lol.
If I understood you correctly, regarding Starrider, I can say with 100% confidence that that song would not be performed unless Mick was on stage. That is HIS baby.
Lastly, don't discount the Soundtrack of Summer tour... In 2011 when they came to The Susquehanna Bank Center in Philly (Camden, NJ technically, but NO ONE wants to reference the murder capital of the east coast, lol), Mick performed Starrider and it was magical. I also believe that was his final show before he took his leave of absense due to health.
So maybe our Starrider dreams will come true this summer, assuming Mick is on stage for some of the SOS tour....... (crosses fingers....)