There are a few pitchers to keep an eye on in camp who might be able to offer critical depth beyond the starters that we already know about: Kirkman, Scheppers, Harrison, Bush, Feldman (mid-season). There were some really good reports about Brett Tomko when he moved into Oakland's roto at the end of 2009, and his velo was still sitting low 90s at age 36, but he spent 2010 rehabbing and didn't make it out of AAA. He's a guy who might surprise some people but at 38, I'd rather take a look-see at our younger arms even if it isn't pretty.
For the most part that means bullpen depth, and most of the starter depth can also fulfill bullpen roles. Guys who already have 2 decent pitches and command can contribute in those roles right away: Hurley, Kirkman, Scehppers, Harrison. As for the rest, well your really only talking about Pedro Strop. If Feliz makes the roto, then Strop should be the guy making the squad while the starting depth, well, starts (in AAA).
I think that outside of Strop and the starters, the pen depth in AAA is not all that impressive. Eppley is a bit of an unknown and right now profiles as a rightie specialist until develops an more effective offering vs LHB. I've never been a big Zach Phillips fan but if he puts it all together he can be fringy middle reliever. There is no more reason to be excited about him than say, Doug Mathis. I think he is working on another pitch to throw vs LHB as well. Beau Jones, well, when you catch him on a good day, he looks pretty good but he has some makeup issues along the line of what ails Matt Harrison. So, he's a bit of a long shot. It's probably unlikely that any of the AA arms would make the jump to the bigs before September, but Fabio Castillo would be the guy likely to break through. Hamburger really made strides last year and a guy like Miggie de los Santos or Jake Brigham could be fast-tracked to AAA as relievers. Aaron Fitt says that Texas will challenge Brigham with an assignment to AA (which i think is unlikely but that is what he said). There are other breakout types, but who are unlikely to break into bigs next year.
There are no stars there really, but Strop and Scheppers could look really nice in that pen while Kirkman might take a step forward and become a mid-roto caliber starter. If Hurley makes a contribution to Texas as a starter it will likely be next year when he is completely stretched out and prepared for 30 starts. Harrison's stuff can be great but his pitchability and makeup are suspect, and he's injury prone; this has to be the year for him. I won't easily give up on a lefty who touches 98 but I will if he doesn't finally put it together this year.
Y. Tateyama is really a bit of an unknown and at 35 is probably not much more than a specialist of some sort, providing nothing more than injury depth at best. Other than that, Zach Jackson, Seth McClung and Y. Brazoban all bring ML experience but not much upside. Jackson was terrible in 2010 in the minors and also bad in winter ball. Brazoban's ML experience was in 2004-2005 and he pitched in the Mexican league in 2010, so... Seth McClung is not a starter contrary to some reports, as the last time he manned that role full time was in the minors during 2002, and has not even been a spot starter since 2008. Yeah, he's a middle reliever type now who might get a spot start or two but who will likely have his innings limited in that role, having not pitched in a year, so, it doesn't seem the role would be a good fit for him. Ty Taubenheim is a 4A starter on the squad to eat up innings when needed.
So who are a few of the position player prospects who might end up making important contributions in 2011. Well, Chris Davis, Chad Tracy and Jose Ruiz might get an opportunity to get some at bats. In the OF, Endy Chavez and Craig Gentry will likely get some time as 5th outfielders when needed. Outside of those guys, the only other guys likely to help the club are Taylor Teagarden and mabye Robinzon Diaz, as injury replacements. Not too much to see here in terms of upside. No Justin Smoak or anything but I like this group of position players as they all seem to have one clear area of strength that they can offer in limited roles should they succeed. Chavez, Gentry, Teagarden offer up defensive attributes. Diaz is a guy with zero patience, but makes a little contact and has a strong arm, but whose catchability is suspect - a nice 4th catcher if you need one. Davis is likely only a platoon bat as is Chad Tracy, should his other hit tools be good enough. Jose Ruiz is a bit of an unknown who disappointed last year. Right now he seems to profile a guy who can make contact but that is all we can say really. I like Endy Chavez as the guy who makes the biggest contribution here as he has had even splits for his career except for the 15 months before his injury. So if he can hit lefties better, and is healthy, I like him over Gentry but both are nice as 5th OF and Gentry is 6 years younger and has that canon arm we all like, but he ain't gonna hit.
Again no stars here, but depth guys who could play important roles throughout the year, and guys who you like to root for to boot.