Tyler's a known quantity at this point. He's the guy that anchored a front court that ranked 233rd in the country in rebounding last year.
He plays hard, but he's marginal at this level - we need rebounding and he's a guy who will deliver 3.5 rebounds in 20 minutes a game. He's had two double-digit rebound games in his career and they were back to back against Maine and Coppin State two years ago. All things considered, Giffey is a more productive rebounder than Tyler - if he gets 21 minutes again this year, we're not very good.
Far better to sink or swim with the higher upside of Brimah and Nolan and keep Olander as a five-foul plan C at center.