Andrew went to hospital for an X-ray after being forced off in the first half of Saturday's home defeat to Millwall and missed the midweek draw with Crewe.
"It is inconclusive at the minute," Hill told the club's official website
"He's in a boot but they're not too sure whether it's an old fracture, a new fracture or a happened-at-sometime fracture.
"But we'll get to the bottom of it.
"He's not feeling in too much pain at the minute and he's optimistic, so we're optimistic."
Source : PA