This is exactly my thought. He wouldn’t be the first guy who was limited to cross-training for a couple weeks prior to a big race (I seem to remember one of the men’s NCAA 1500 or mile champions of the last decade—Henry Wynne, maybe?—who did nothing but aqua running for something like two weeks prior to the meet.) You can’t know exactly how much it’ll affect your racing unless you get out and give it a try. Hocker did that…and found out he didn’t quite have enough back yet.
But if he’s not actively injured still, then he should absolutely consider racing the 5000 (and hope the 1500 three days earlier will maybe perk the legs up some). The only risk I see—not knowing the injury but assuming he’s indeed fully healed—is the potential loss of confidence if he gets roundly beaten a second time in four days.
Unfortunately, I do think that’s a possibility, since I don’t think he has much of a chance in the 5000 even if he was at full strength. Going in, I’d favor Fisher, Kincaid, Chelimo, McGorty, Teare, Bor, and Nur over him in a 5000 right now. The odds of him beating all but two of those guys—and the rest of the field—seem pretty low, especially with compromised training.
But if he does run, it doesn’t follow that he wasn’t injured or that the injury didn’t affect his performance.