Winn was scratched from the lineup for Wednesday's game in San Francisco due to left thumb soreness, Derrick Goold of the St. Louis Post-Dispatch reports.
Hjerpe will remain on a starter's schedule for the Cardinals down the stretch and is currently penciled in to serve in a piggyback role with Kyle Leahy, Derrick Goold of the St. Louis Post-Dispatch reports.
Walker is absent from the lineup for Wednesday's contest in San Francisco.
Mathews (1-3) allowed two runs on five hits and two walks while striking out four over six innings to take the loss versus the Giants on Tuesday.
Webb blew the save Tuesday against the Brewers, giving up two runs on two hits and no walks while striking out one over one inning.
Peterson allowed one run on six hits across 4.1 innings and did not factor into the decision in Tuesday's 4-3, 10-inning loss to the Brewers. He walked three and struck out four.
The Cardinals activated Winn (thumb) from the 10-day injured list Tuesday.
Baez isn't in the lineup for Tuesday's game against the Giants.
The Cardinals optioned Prieto to Triple-A Memphis on Tuesday.
Ramirez is absent from the lineup for Tuesday's game in Milwaukee.
