Trouble is he shipped out several players and didn't replace them. He'd have more to pick from if he hadn't inexplicably decided to get rid of Knockaert, Locadia and Andone without replacing them. Also he didn't seem bothered by not signing anyone in the January window when nearly all the fans were crying out for the club to sign another striker. So yes he can only pick the players he has but he could have had several more to choose from but doesn't thanks to his decision.
*EDIT* I see you've basically replied to a post similar to mine already.
Knockaert (sulky, no better than what we've got), Locadia (wardrobe/DJ), Andone (nut job). It's not difficult to read between the lines and guess why those 3 weren't wanted around the squad.
And as for not being bothered in Jan, what does a manager do if the club can't provide a suitable striker? He has to say he's happy and back the current squad. What's he going to get from the players he's left with if he's publicly saying they're not up to it?
***Edit: Locadia scored on his MLS debut, which no doubt will send some into a complete meltdown. For a sense of perspective, Bradley Wright-Phillips is a scoring legend in MLS***