I'm seeing this question or its close relatives a lot today. Sort of addressed it earlier. I do think Missouri can finish better than my preseason prediction based on a couple factors.
1. Tilmon and Geist (and sometimes Mark Smith) are playing like All-SEC candidates. Geist is 10th in the league in offensive rating. Tilmon is 13th. Only two SEC players under 6-4 have better offensive ratings than Geist. Tilmon is a top 10 rebounder in the league. They are two guys who have raised their level of play since Porter got hurt.
2. The league isn't as good or deep as we thought. Georgia, South Carolina, Alabama, Texas A&M, Ole Miss are beatable. Arkansas, Florida, Vandy, LSU all have decent talent. Missouri can beat those teams when things are going right. The other four are a cut above the rest of the pool - Tennessee, Auburn, Mississippi State and Kentucky - and MU plays three of them on the road. But those were always going to be challenging games, with or without Jontay.