His size is not the problem. He does not hold onto the ball. The skillset you need at his position is not what he possesses as a player.
On the contrary, Mike Williams does not have the size, but he has the skill and will. Omoyuri, and Freeman,too.
You seem to be back on offense. I readily concede that's not Sa's strength - defensively, though, he's been solid. Defense and rebounding he does pretty well - and those are Pike's key areas of focus. He doesn't seem to have the skillset to light up the scoreboard.
"Skill and the will" works for rebounding, fighting for loose balls, and clogging passing lanes... but it doesn't work when you're being backed down on the block by someone who has 50 pounds on you. A 6-9, 227 Sa is not going to be able to defend a guy like Haas at 7-4, 290 - no matter the skill or the will - so you're not likely to see him out there at the 5 when Haas is on the floor, unless we're in serious foul trouble. Doorson will be asked to put a body on him at 7-0, 275... but Haas has much more quickness.
So far, Sa has seen >6 minutes against four teams:
NJIT - biggest player was 6-9, 235
Coppin St - biggest player was 6-8, 210
Cleveland St - biggest player was 6-9, 220
Central CT - biggest player was 6-9, 220
Doorson has seen >5 min against the other 5 Div-I teams:
Mich St - biggest player 6-11, 242
Minn - biggest player 6-10, 257
FSU - two 7-footers at 233+
ECU - biggest 6-10, 235
Bryant - biggest 6-10, 190
Slower, bigger centers saw Doorson check in.... smaller, faster centers saw Sa check in. That's likely how the rest of the season will go, too.