There's no way that Luke Harangody is getting more minutes than Jermaine O'Neal unless JO gets hurt.
The fact that Doc has gone with lineups of Nate, Rondo, Daniels, PP, and Glen Davis at times this year tells you all you need to know about what Doc thinks of Luke's ability to contribute. Let's also keep in mind that Jermaine has immediately passed Erden on the depth chart, and Erden was someone Doc clearly thought more highly of than Harangody.