Steamer600
Cola - 108 wRC+; 1.1 fWAR
Pedro - 112 wRC+; 1.1 fWAR
Smoak - 96 wRC+; 0.6 fWAR
Pearce - 110 wRC_; 2.0 fWAR
Pedro is a career 118 vs. RHP while Smoak is a 101.
Colabello is a 113 vs. RHP but contrary to what Grant thinks, that split has little meaning.
Pedro would improve the team's offense vs. RHP but is it worth the drop in defense from Smoak, and is it worth (presumably) the increased payroll? He was projected for I think $8M in arbitration so he'll look to approach that figure.
You would lose roster flexibility by replacing a switch hitter with someone who can't hit lefties. You would gain some by adding an emergency 3B, though.