Reasonably in the mix for next season on the infield (pre-Vladdy):
Diaz
Drury
Gurriel
Martin
Solarte
Travis
Tulowitzki
Urena
2B: TRAVIS, Gurriel, Diaz, Drury, Urena, Solarte (Martin)
SS: GURRIEL, Tulowitzki, Urena, Diaz (Drury, Solarte, Martin)
3B: DIAZ, Drury, Solarte, Martin (Gurriel)
Each position is more or less sorted by what I figure is role suitability/likelihood. CAPS name is the guy who I think has the best shot at the opening day gig. (parentheses) are guys who are more like emergency deployments at that position, not likely to get real consideration for regular innings at the position.
they basically have 3 starting spots and a bench spot to give to 8 guys, and then it only gets tougher when Guerrero forces his way up and you take away that primary 3B spot.
I think my ideal setup to begin would be Travis at 2nd, Gurriel at short, Diaz at 3rd, Drury as the utility IF and Martin on the bench as a super-sub infielder/3rd catcher/mentor type. Trade Solarte, start Urena in the minors at short as the primary call-up guy, and find any way possible to tell Tulo he's too broken to play. When Guerrero comes up then you can make a decision on whether or not Travis is flunking his chance to be the everyday 2nd baseman. If he has, you move Diaz over there and slide Guerrero in. If he returns to form, then you've got some decisions to make on Diaz/Drury/Martin.
EDIT: aww hell, I don't know how to do tables on nuHF. GImme a minute to rejigger this.
EDIT 2: It's not as visual as I wanted, but this will have to do.