The only problem is that it's impossible to bench either of them right now.
Best is banging them in and he's the form of his career by a mile, playing so much better than anyone thought he could, and after a slow start Ba is starting to show the quality player he really is.
this more or less, HBA will get his chances but why rush him into the side when Ba and Best are both in form? Just keep with the sub appearances for now to help build up his fitness, at the end of the day he has missed a year of football and it would be foolish to expect him to just jump into the side so soon.
On a side note I was impressed with the Ba-Best partnership last week and imho it shows promise but these things take time to really form