I look at it more as, how would he have helped the Cardinals this season?
One of the Cardinals' biggest weaknesses this season has been a lack of production at the leadoff spot.
KW has averaged .279 with a .338 on-base percentage and a .449 slugging percentage as the Brewers' leadoff hitter.
You're right injuries have cut into his impact.
No debate there.
But yes, I think he would have helped the Cardinals a lot.
He would have helped keep Tommy Edman from being overexposed and could have made Edman the fill-in outfielder for the Harrison Bader and Tyler O'Neill injuries earlier this season because he would have been playing second base.
For all of his injuries he's still fourth on the Brewers team in at-bats.
Cards convinced themselves they couldn't afford to keep him, and I think it was a mistake.