A few things have been reported over the last few days regarding the likelihood that the Mavs trade this pick. First, the projected cap numbers came out lowering than expected. This means the Mavs will need to clear more cap space than expected and not having to save a $1.6 million cap hold for the 13th pick sounds even better than before.
Second, Chad Ford tweeted about the rule regarding the how the cap hold can be avoid if a foreign player is drafted that does not intend to play in the NBA that season. Meaning if the Mavs spent the 13th pick on Dario Saric and the Mavs & Saric agreed that Saric would not play in the NBA in 2013-2014 season, and the Mavs sent a letter to the NBA acknowledging this agreement, then the $1.6 million dollar cap hold would be lifted. This seemed to give the Mavs an out where they could use the pick without having to deal with the cap hold, making it seem likely the Mavs kept the pick or at the very least didn't have to give it away for less than it was worth.
Lastly, Chad Ford indicated today that Saric is likely to withdraw his name from the NBA draft. As pure speculation on my part, this may be because the Mavs approached him about their desire to reach an agreement not to play in the NBA this year. Instead of being drafted in the late lottery and then not even getting to play in the NBA for at least year, he decided to continue to compete and Europe for another year and try to improve his stock for next year. But if Saric withdraws his name, the Mavs could still try to reach such an agreement with one of the other European players (Antetokounmpo, Karasev or Gobert, for example). But if they don't like those players or can't reach such an agreement with one of those players they like, that puts the 13th pick squarely back on the trading block.
In other news, Chad Ford had Muhammad going to Celtics at 16 in his latest Mock Draft 4.0, so if the Cavs were able to obtain the pick, Muhammad would theoretically still be on the board.