It takes experience to be a good post defender. T-Rob is a super athletic, shot blocker, rebounder ... but he was always out of position defensively, and opponents can easily fake him out with a spin move or drop step. He was being schooled by more experienced bigs like Hansbrough, Scola, Shawn Marion, etc. because he didn't know where to be on the floor.
His problem last year was he kept getting lost in the defensive scheme/rotation, often leaving his man wide open. This was a bigger issue in the limited time he got earlier in the season and seems to have gotten a bit better when he got his opportunities near the end of the year. Hopefully he improves significantly on this front over the summer. When he's in the right spot, he can be pretty disruptive-- long arms, pretty good athlete, strong body. But he has to be in the right spot first.
He has high upside on defence, but it is unknown whether or not he will reach his potential before his next contract. Like CH said, he did not have the rotations down yet. Will he be at his peak defensively? No, but he will be much better than Delfino against PF's (or Harden against Ibaka in the playoffs).
Look what he did in the playoffs and towards the end of the regular season when he finally got the inutes and got comfortable. From watching him in college I can tell you he's a natural shot-blocker.
D-League...!!!! Dude he had 11 blocks in two straight NBA games and you bringing up D-League games...Lol...
The D-League also has D-League statisticians. Blocks, steals, and assists are the most screwed up basic statistics in basketball. I am guessing that Jones lost some blocks that weren't tallied. Lin lost a huge amount of steals when he was in D League (yes, I actually watched his D League games), and he even loses steals to the statisticians in NBA games, and he is certainly not alone.
His defense was the only thing that was holding him back. If he was just an average defender who can hold his own, TJones wouldve started the first game last season. TJone actually earned a starting job at last game of preseason game, beating out Smith, DMo, and Morris (PPat was injured if I recall). It was very significant because it was the last game before the season began. If he did well, starting 4 was his, but as it turned out, he was absolutely awful against Davis. He played 5 minutes and never returned. That was the turning point for him. Instead of starting at 4, he ended up playing with Vipers for most of the season. Edit: That last preseason game was also a turning point for GSmith. He was on the verge of last roster cut. He did a tremendous job on Davis and earned himself a roster spot.
Not true-- at least not the level that Terrence Jones was at to start the season. He was worse than most of his fellow PFs. This is why the coaches benched him most of the season. Patterson was at the right spot in defensive rotations most of the time. Morris was also significantly less lost than Jones was. Getting lost in the defensive scheme is a fairly common rookie problem and many players get much better at it as their careers go on. A good example is Jordan Hill-- I always had a ominous feeling of doom when he stepped on the court in 2010-11 because his penchant for screwing up defensive rotations and offensive play. But he got better and was pretty good as a Laker. I think Jones-- as well DMo, Smith and other young players-- will get better at it. Some guys are just stupid (see Swift, Stromile) and you can't fix stupid. But Jones doesn't seem to be one of them (at least judging by my limited knowledge of the guy).
Good weak side shot blocker, and defensive rebounder. Capable perimeter defender. Could improve in Defensive rotation and setting better screens.
A little BS? Of course he was worse than Pat. He was a freakin rookie that has never played in McHale's rotation before. Morris was lost over his place his rookie season. Of course he had one year of experience over Terrence.
Most of the young Rockets last season seemed coachable. The one exception being Royce White. Some guys just don't mentally process the defensive stimuli quickly, though.
Quit getting defensive. I noted that defensive rotation is a common rookie issue in my post and said that guys often get better. But it was an issue for Jones-- and it is an issue that he'll have to work to improve upon. Some guys never manage to fix it for whatever reason.