The battle for positions in the Giants bullpen is heating up and getting interesting.  So far, there have been 3 significant events shaping the bullpen:

1.  The emergence of Merkin Valdez as a potential dominant 7'th inning/setup/closer-in-waiting.  I assume Valdez needs no introduction to this crowd.  He's coming off TJ surgery and is reportedly hitting 96 MPH with consistency so far.  Surprisingly, he has also displayed a decent slider and changeup which allowed him to freeze 3 batters in an inning two days ago for called third strikes.
2.  The collapse and option of Randy Messenger.  Messenger hasn't been right since he broke his left(non-pitching hand) striking the dugout/clubhouse wall last season.  He was getting rocked in ST, and possibly more importantly, was showing a lot of very bad body language on the mound.  The demotion came as a surprise this early in ST.
3.  Noah Lowry's injury.  Lowry's absence has created an opening in the rotation.  The three logical candidates would seem to be Jonathan Sanchez, Pat Misch and Brad Hennessey.  Hennessey got a start today, but Bochy insisted that he is not a candidate for the rotation.  He was just filling in for Tim Lincecum who's start was pushed back due to a mild groin strain.  Sanchez has been very shaky so far, and appeared to be headed down  to Fresno himself, but he pitched halfway decent today allowing just an unearned run in 3 IP.  Misch gets the start tomorrow in what is being advertised as an audition for the rotation.

Here's where it stands right now:

1.  Brian Wilson is the closer.  He's been a bit inconsistent, but it looks like Bochy is going to see him through into the season barring a total collapse.
2.  Tyler Walker is the setup man.  He can close if Wilson collapses, but would probably be better in the 8'th inning role.
3.  Valdez looks like the 7'th inning guy.  In fact, Bochy has started running Valdez, Walker and Wilson out in order on the same day to set up that rhythm.
4. The emergence of Merkin Valdez would seem to push Brad Hennessey back into a middle/long man role for which he is well suited but might be miffed that it is a demotion.  He would also seem to be a logical choice to take Lowry's spot in the rotation, but it seems Misch and Sanchez are ahead on the depth chart.
5.  Despite some bluster about 11 pitchers early in ST, Bochy is talking more about 12 now, not a surprise.  If Wilson, Walker, Valdez and Hennessey are locks, that leaves 3 more spots up for grabs among Steve Kline, Jack Taschner, Erick Threets, Vinny Chulk, the loser of the competition for the rotation, and several others.

Taschner and Threets have pitched fairly well.  Interestingly, Taschner, who has two seasons of MLB experience, has an option left, but Threets is out of options.

Steve Kline has absolutely stunk up the place.  I imagine he is a lock due to his veteran savvy, but it's real hard to swallow him blocking a more deserving younger player.

Vinny Chulk is recovering from Burger's Disease, a circulatory disease caused by smokeless tobacco.  He started out shaky, but is starting to put together a string of strong outings.  If he continues to pitch well, Bochy will want his veteran presence on the roster.

Jose Capellan, the rule 5 draftee, seems to be pitching himself back to the Boston organization allowing runs in almost every appearance so far.

A name to watch is Barolome Fortunato.  He is a hard throwing RHP, NRI, who has pitched very well, including pitching his way out of a no out bases loaded jam today with a run scoring GIDP and another groundout.  I expect he will start the season in Fresno and ride the Southwest shuttle to SF.

Another interesing development in the last few days is a couple of dominant outings by Bill Sadler with none of the poor control that has dogged him in the past.  Sadler probably also has no shot at making the big club out of ST, but he could be moving up the depth chart for in-season callups.