The aim of this study was to determine whether patients treated with platelet-poor plasma (PPP) after an acute thigh muscle injury would have a faster return to activity compared to patients treated with platelet-rich plasma (PRP). This quasi-experimental study included 100 patients (ages 16-45) with an acute thigh muscle injury diagnosed by sports ultrasound and treated with either PRP or PPP followed by a course of structured rehabilitation. The primary outcome was the number of days until unrestricted participation in sport, while the secondary outcome was the rate of recurrent injury within 12 months. The time until full, unrestricted participation in sport was significantly lower in the PPP group compared to the PRP group for all injury grades, with patients in the PPP group on average returning to unrestricted participation in sport 22.89 days more quickly than the PRP group (p < 0.001). Additionally, no significant difference in recurrent injury up to 12 months post-procedure was seen between groups (p = 0.967). PPP resulted in faster return to sport than PRP for acute thigh muscle injuries with a non-inferior injury recurrence rate. These findings suggest that future high level studies comparing PPP and PRP for the treatment of thigh muscle injuries should be considered.