I suppose the thing one needs to know is what constitutes a "breakout."  If it's a universal world-beating type of year then maybe the Astros don't have that player on the roster.  But if we're talking about a better than expected performance then maybe just about the whole team is ripe for such a year, except perhaps the three who in my opinion had their breakout last year:  Altuve, Lowrie and Harrell.

I think Lyles is on an upward path.  I think he improved last year in both quality and quantity of work.  The quality may not be so apparent going strictly by the numbers, but the quantity reflects the quality.  A lot of pitchers' numbers are affected by team performance, so I'm not expecting him to win 30 games this year, but I think the expectation will become that games he starts are very likely to be competitive, even with the Astros offense. 

Maxwell seems to have all the tools.  If regular work gives him the patience to draw a few more walks he might become the right-handed Adam Dunn.  But he does have a big strike zone to defend and the strikeouts are bound to be a part of his profile.

The two position players I might have the highest hopes for are the Martinezes.  JD may have already had a breakout year but it was divided between 2011 and 2012.  The last half of 2012 was something of a disaster, but there are a lot of players who have had great careers after having the hamate bone surgery and I'm really hoping that happens for JD.  I thought that Fernando's second call-up last year was an eye-opener.  It'll be interesting to see how the AL pitchers react to him and conversely how he reacts to them.  In terms of being currently under the radar his year could be the one most characterized as breakout.  He's just a year older than Springer and he's playing at 2 levels higher.

The late season heroics of Dominguez probably have him on everyone's list to have a nice year and we all hope so, but it's still early in the game and it'll be interesting to see how the season wears on.  Altuve's 2012 season is a good example of how a great start can cover up some bad stretches (or overall decline?) later in the season.  I expect Dominguez to start out strong but as a young player (he'll be 23)  he may wear down during the season unless given a lot of relief.  I think Wallace could see a lot of time at 3rd for this purpose.

As for Wallace himself, I don't see a breakout year exactly, if for no other reason than how he'll be "utilized," pun intended.  I expect him to rotate between 1st, 3rd and DH, and I think that could be tough on a player who hasn't really extablished himself.  But if Singleton doesn't force himself onto the ML roster Wallace could still play a nice role on the team.  I root for him because I know when someone has lost as much weight as he has I know he's really working.

Totally unknown (as if any of the above is otherwise):  Freiman.  I hope he can adjust to a 2-level jump well enough that makes me learn how to spell his name correctly.  His numbers have improved as he's moved up in the minors, so maybe, just maybe ....

The sleepers to me are the two new starters.  Pitching is very esoteric to me.  Guys succeed with speed and/or guile.  Guys bomb out with seemingly the same stuff.  I don't know if it's Freudian or Jungian.  It's one of the black arts.  So White and Ely are big mysteries to me.  Ely is older, having toiled at AAA for several years.  But his numbers last year in the PCL are staggering to me, so I'm hoping it's a case of the lightbulb - whatever that might be - coming on at last.  White's numbers last year at Colorado look somewhat similar to Lyles's in 2011.  His WHIP is high (similar to Lyles) and his K/BB rate is low (lower than Lyles), so based strictly on numbers I 'm not overly impressed, but he's still young and maybe on his way up.  If either one of these guys can find the magic mojo it could be the difference-maker to the Astros regaining major league credibility.  I've got my fingers crossed, but I'm not holding my breath.  But if it happens for either of these guys then that's the big breakout of the year.


The big breakdown of the year:  I'm very concerned about the decline of Altuve during the year in 2012.  It's uncertain whether it's a matter of fatigue or pitching adjustments.  Since there's now a "book" on him I wouldn't expect 2013 to start out so spectacularly for him to cover up a more pedestrian late season and I wouldn't be totally surprised if Greene or Gonzalez wound up as the regular 2nd-baseman by season's end.