Please help improve my team

[OKDaddio]

16 team H2H Yahoo League
R/H/HR/RBI/SB/CS/K/GIDP/E/AVG/OPS - W/L/SV/HR/BB/K/ERA/WHIP/KperBB

C M. Barrett
1B J. Morneau
2B P. Polanco
SS J. Hardy
3B M. Ensberg
OF J. Hamilton
OF G. Sheffield
OF A. Soriano
U C. Delgado
BN T. Iguchi
BN J. Peralta
BN C. Patterson
BN W. Helms

SP C. Shilling
SP S. Kazmir
RP R. Betancourt
RP F. Cabrera
P A. Burnett
P C. Zambrano
P G. Chachin
BN J. Suppan
BN A. Wainright
BN Z. Duke
BN P. Hughes
BN S. Linebrink

When this team was drafted I thought I had a pretty strong squad. Right now I'm in dead last place though. I've been chalking it up to having some severely underproducing stars (Soriano, Sheffield, Delgado) and weak RPs. Should I just ride this out and hope for my big sticks to turn it around or should I start thinking about making some changes? Thanks in advance.