Boyd (8-3) took the loss Wednesday, allowing one run on three hits and two walks over six innings as the Cubs were downed 2-0 by the Diamondbacks. He struck out five.
Atlanta claimed Vanasco off waivers from the Tigers on Wednesday and optioned him to Triple-A Gwinnett.
Cubs manager Craig Counsell said Wednesday that Brown (neck) suffered a setback during his live batting practice session Tuesday, Meghan Montemurro of the Chicago Tribune reports.
Happ is not in the lineup for Wednesday's contest in Arizona.
Conforto is out of the lineup for Wednesday's game against the Diamondbacks.
Webb (6-4) allowed two runs on one hit and one walk without recording a strikeout in one inning, taking the loss and a blown save in Tuesday's 5-4 loss to the Diamondbacks.
Happ went 1-for-4 with a three-run home run in Tuesday's 5-4 loss to the Diamondbacks.
Holmes allowed two hits and two walks while striking out five over seven scoreless innings in a no-decision versus the Diamondbacks on Tuesday.
Albies went 2-for-3 with two RBI in Tuesday's 4-3 win over the Dodgers.
Iglesias recorded a save Tuesday against the Dodgers, allowing one hit and one walk while striking out one over a scoreless ninth inning.
