After looking at rpiforecast with conference tournaments included, it looks like 20 is actually the magic number of wins UT needs to make the tournament. I'm not usually big on a specific number of wins, but if you look at the projections, every scenario with 19 or fewer wins (with the lone exception of 19-15, the unlikely scenario where UT loses all remaining regular season games and wins the SEC tournament) results in a rpi of 58.6 or worse, which will be very likely to miss the cut.
Every scenario where the team has 20 or more wins results in a rpi of 50.2 or better, which should be in the field.
5-0 through the end of the season, and I think they dance even with a first round loss in the SEC tournament. 4-1, which I think is likely, puts them in a place where they need a first round win or they are likely to miss out. Anything worse than 4-1 through the rest of the regular season will put them in a very difficult position.