Moving The Ultimate Fighter from Fridays to Tuesdays seems to have done the trick to bring the ratings up, although it's still not matching the levels seen for the first 14 seasons on Spike TV.
Dave Meltzer has the details at MMA Fighting:
The Ultimate Fighter seems to have settled in at what will likely be the normal level of the season as Tuesday's show did 1.25 million viewers. It was up five percent from the prior week.
After four weeks, the show averages 1.31 million viewers in its new time slot, a number helped by the 1.51 million viewers for the season premiere. It is pretty clear cut at this point that the show on Tuesday will significantly beat the prior two Friday night seasons on FX, but also fall short of the numbers the show did during its run on Spike from 2005 to 2011.
In addition to the move to Tuesdays, the UFC considerably upped the star power of the coaches by bringing in Light Heavyweight champ Jon Jones and the notorious Chael Sonnen as the season's coaches. Sonnen will challenge Jones for the LHW title at UFC 159 in April.