3rd baseman Mark Sobolewski was drafted by the Twins from the Blue Jays in the AAA portion of the Rule 5 draft. Sobolewski was a 4th round pick by the Blue Jays ($243,000 signing bonus) in '08 and was ranked by Baseball America as the 19th best prospect in the organization after the season. However, he was never ranked in the top 30 again.
The 25 year old right-handed hitter showed some power in 2012 in AA, with a .202 ISO (.131 was league average) in 91 games. Even though New Hampshire's park played slightly hitter friendly in 2012, his ISO was better on the road than it was at home. It was a drastic improvement from 2011, when he spent the whole year in AA and had just a .110 ISO. The repeating of the level along with being slightly older than the competition most likely helped Sobolewski. Strangely, he had a slightly higher ground-ball percentage and lower outfield fly-ball percentage in 2012. His HR/OFB% jumped from just 7.9% in 2011 to 22.8 %, which seems really fluky or at least really odd. His career ISO in the minors (obviously the different parks and levels create variables) is .127, suggesting that, unless he has added serious power in the past year, that he is not much of a power hitter. He also has a pretty high strikeout rate in his career at 21.4 % with a pretty low walk rate (6.11 %).
BA did rank him as the best defensive 3rd baseman in the Eastern League in 2012. Early in his career, RTZ ranked him as a below average 3rd baseman, and he has actually lost a little range according to Range Factor since then. According to that measure, he is below average and comparable to Kevin Youkilis and Pedro Alvarez (out of MLB 3rd baseman) in 2012. Just to compare him to a few of his peers, he is better than Cody Asche (who I don't think is very good defensively) and Jefry Marte according to that metric, but he isn't near as good as Kyle Bellows. FRAA also gives him similar results, rating him as below average. In going back and watching him, he definitely has the arm to play 3rd base, but he does seem to suffer when it comes to hands and reaction times.
He also doesn't provide much as far as speed goes, as he has just 11 career steals in the minors, and speed scores of just 1.5 and 3.4 over the last two years in AA. This may have a little correlation to defense, as above average defensive 3rd baseman usually have better speed scores than Sobolewski's, and it is somewhat of a baseball truism that the more athletic you are, the easier it is for you to play good defense (of course there are notable exceptions). In fact, when you watch him at the plate, he looks like he sort of built like a 1st baseman. He takes a long stride at the plate and has a long and slow swing. There is definitely some power potential in the swing, especially on low balls where he can use an uppercut hack. It seems, at least to me, that his lack of power is not because he isn't very strong or doesn't have the build. He appears to be very strong and has a good build. The problem seems to be with his approach and with his overall swing mechanics. An optimist could perhaps say that 2012, at least in AA, was him putting it all together and finally hitting for the power that the Blue Jays thought he was capable of when they drafted him. I still don't like where he holds his hands, and it seems he is really susceptible to the high fastball.
Toward the end of the year (though he was sent back to AA for the last few games of the season), Sobolewski got promoted to AAA, but because of small sample size (23 games) and the nature of Las Vegas, it doesn't even make much sense to look at those statistics. It does give us a little more pitch data than we would see in AA, and the tendencies seem to be (small sample size alert, but these numbers stabilize quicker than most of the rest of the numbers) that he sees less pitches than average, as he swings at more pitches than average and makes more contact than average. He also seems to be a hitter with reverse splits, at least this is the way things have played out over the last couple of years. He has a slightly better K/BB against lefties, but he has hit for more power against righties. The warning is that this could be fluky, as he has a better LD/GB/OFB against lefties, while his HR/FB% and BABIP is much better against righties. The latter usually regresses to the mean, so there is a good chance he is a fairly normal hitter when it comes to platoon splits.
To me, Sobolewski's chances of ever reaching the Majors rely on his 2012 AA power being for real. He will most likely have to transition to first (unless the Twins are just willing to live with the bad 3rd base defense), so he will really have to hit. Without much OBP value or plate discipline, power will have to be Sobolewski's ticket. I don't think there are a lot of good reasons for expecting him to hit for 1st baseman type of power in AAA or the MLB.