To examine match running performance recovery trajectories following muscle strain injuries of varying severity in professional male football players upon RTP. Forty-nine outfield players from a professional football team were prospectively monitored over four consecutive seasons (n=168 non-contact lower-limb muscle strain injuries). Injuries were classified by severity (time loss) as mild (1–7 days), moderate (8–28 days), or severe (> 28 days). GPS-derived match metrics were analysed across the four matches preceding injury and across 14 matches following RTP (i.e., POST 1-to-14) to characterise the recovery trajectory. Generalised additive mixed models were fitted to describe nonlinear recovery patterns. Recovery trajectories differed significantly between severity groups (R² 95%IC = 0.360 to 0.425, p < 0.001). Mild injuries caused short impairments with reductions of -19 to -27% in match running metrics at POST1 (ES: 0.25 to 1.05) that persisted up to POST2; per-minute intensities remained largely preserved. Moderate injuries caused large impairments, in sprinting, high-speed running, and accelerating/braking actions (-62% to -92% at POST1), and remained below baseline at POST3 (ES: 0.24 to 3.12); per-minute metrics revealed some residual neuromechanical deficits beyond minutes restriction. Severe injuries caused similar pronounced acute impairments (-60 to -100% at POST1) but the longest persistent deficits up to POST4 in absolute metrics and up to POST7 for high-speed running (ES: 0.28 to 2.31). Match running performance in the RTP after muscle strain injury follows a clear severity-dependent recovery: mild injuries recovered within two matches, moderate in three, severe injuries after four or more, particularly in high-speed and accelerating/braking actions.