Yes and no. spoilers:end of spoilers
Lindsay maybe hasn't come back from Madripoor yet -- when the last series ended Lindsay had unfinished business there she needed to resolve. I agree that Roger wouldn't likely be the FIRST call Jessica would make if she needed a sitter, but sometimes the regular sitter isn't available and you have to call on your back-up options.
As for Roger abandoning the baby, if Gerry was asleep in his crib at the time when Jessica was erased and Roger wasn't in the baby's room to see him he would not have had any clue that there was a baby there. He would just suddenly find himself in a strange apartment...and left. Its tragic and horrific but technically not him 'abandoning' a baby if he didn't know the baby was there. And then Hydra swooped in and grabbed the kid before anyone could remember him and come looking.