Scott Feldman - Many will write his 17-win 2009, but based on Pedrophile's scouting report, he may be for real.  He has a low-90s fastball with good location, a great cutter, and a good change, with a curve and slider in the works.  Still, his K/BB was pedestrian and plays half his games in a hitters paradise.

Gio Gonzalez - Has struggled with consistency in majors despite good minors numbers and great K rates at any level.  This spring he has shown a lot of the same, though it wouldn't take that much more control or consistency to give him value for Ks alone.  The great outfield D should help him some, but he may not start the season in the rotation at all.

C.J. Wilson - One of the more intriguing guys that everyone will probably forget, he's gonna be the Rangers 5th starter.  He'll have to perform to not get the axe when Feliz and/or Holland come knocking, but Wilson has quality stuff and if it translates well to the rotation he could be a solid starter, perhaps doing a Justin Duchscherer impression (hopefully minus the injuries).  I'm really curious to see what the Minorleagueball community projects for him in 2010.

Colby Lewis - Yes, another Texas pitcher.  He dominated in Japan and has always had great potential, and ratings systems ZIPS, CHONE love him, but it remains to be seen how he'll transition from Japan to the AL West in a big homer ballpark and all of the factors that go with that, including confidence.  He's 30 already and has yet to have a successful stint in the majors, but would make for a nice comeback story.

Fausto Carmona - After his stellar 19-win campaign in 2007, has struggled with his walk rate the past 2 seasons and fell off the face of the planet, getting demoted to single-A.  But he's lost a lot of weight and has been showing much better control in the VWL and spring training.  He still has the power stuff for great GB rates that would make it okay for him to not have a high K rate and still succeed, but expectations should be tempered as he was horrible in 08 and 09.

Ryan Rowland-Smith - More of a safe pick than some of the other guys on this list, but he has had an under-4 ERA the past 2 years even if his K rate is rather average.  Still, he's a flyball pitcher on a team with great outfield defense and will likely get more run support this year as well.

Vin Mazzaro - Unlikely to open the season in the rotation, but with both Sheets and Duchscherer in the rotation, may get another chance soon when injuries arise.  He has a good low-90s heater and is still young enough to improve on his first stint (which if you remember, created quite a buzz of him being an ace after his red-hot start before cooling off fast).

EDIT: I'm now including one sleeper I forgot to mention, thanks DFarth, hope you don't mind me borrowing from you.  He may be a bit down in the votes since I added him late.

Matt Harrison - The former solid prospect has struggled mostly in his past stints with Texas, but the lefty has lost 30 pounds added some serious velocity this spring after missing a good chunk of last year with Thoracic Outlet Syndrome, with his fastball consistently 92-94 topping out at 97, and has been fairly dominant in his spring appearances.  He's also now adding a cutter, and is only 24 years old so his upside is quite high with these new developments.  I honestly had barely had him on my radar before, what are your thoughts  on him?