Pirates director of sports medicine Todd Tomczyk said Archer will not throw for at least a week, then be re-evaluated.
In other moves Wednesday, the Pirates placed right-hander Clay Holmes on the 10-day IL with right quadriceps discomfort while recalling right-handers Dario Agrazal and Parker Markel from Triple-A Indianapolis.
Agrazal is expected to take Archer's spot in the rotation and pitch Sunday against the Cincinnati Reds. The rookie made eight starts for the Pirates earlier this season, going 2-3 with a 4.29 ERA.
Holmes pitched 3 2/3 innings in relief of Archer on Tuesday night in the Pirates' 4-1 win. Claimed off waivers from the Seattle Mariners on July 27, Markel pitched in relief twice for Pittsburgh and allowed two runs - one earned - in three innings.
Archer, a two-time All-Star with the Tampa Bay Rays, is 3-9 with a 5.19 ERA in 23 starts. He has not won since June 6, a span of 13 starts.
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