Who else is available on your wire? Also, do managers trade in your league?
I'd make a decision on keeping Belt or Rizzo...in a non-keeper, Belt should have better season...
...try to upgrade any position quickly (hitter or pitcher) by offering Rizzo as a throw in...this will open up a roster spot...
...I would look to try to get to no bench spots, or at the least one bench spot, for your hitters and get some more pitching...assuming that bench spots can be used on either side...hitters who are starters play pretty much every day, unless they can't hit a left-handed pitcher for example...or if they are catchers...unless you are holding true long-term season value, you are wasting roster spots.
If there is any value in terms of SP or RP on your wire...I'd rather go with the hot hand (unless you have a slumping stud) in your hitter slots...and load up on pitching...in general always pick up value which is what you're doing with Goldschmidt...not sure it makes a lot a sense to hold Belt, Goldschlager, and Rizzo...trade Rizzo while his perceived value is there...keeper league is another story...good luck
10-team mixed keeper league (15 keepers), H2H - 1 Win R/HR/RBI/SB/AVG/OPS/W/CG/SHO/SV/K/ERA/WHIP/QS
C - S. Perez
1B - A. Rizzo
2B - J. Kipnis
SS - T. Tulowitzki
3B - A. Beltre
OF - M. Trout, A. McCutchen, B. Harper
UTIL - J. Upton, E. Hosmer, A. Cabrera, EMPTY
DL - G. Stanton, K. Youkilis N/A slot: J. Profar
PITCHERS: (Lineup: 4 SP, 2 RP, 2 P)
SP - S. Strasburg, A. Wainwright, G. Gonzalez, M. Moore, K. Medlen, H. Iwakuma, S. Miller, W. Miley, A. Cobb, J. Garcia, H. Ryu, T. Cingrani, J. Hammel
RP - A. Chapman, A. Reed, J. Henderson, J. Tazawa, H. Bell