Objectives Patient throughput is an increasingly important cause of emergency department (ED) crowding. The authors previously reported shorter patient length of stay (LOS) when adding a triage liaison provider, which required additional personnel. Here, the objective was to evaluate the effect of moving a fast-track provider to the triage liaison role. Methods This was a prospective observational before-and-after study design with predefined outcomes measures. A "standard staffing" situation (where an advanced practice provider staffed treatment rooms in the fast track) was compared with an advanced practice provider performing the triage liaison staffing role, with no additional staff. Eleven intervention ("triage liaison staffing") days were compared with 11 matched control ("standard staffing") days immediately preceding the intervention. Total LOS was measured for all adult Emergency Severity Index (ESI) 3, 4, and 5 patients (excluding behavioral health patients), and results were compared using Wilcoxon rank-sum and chi-square tests. Results A total of 681 patients registered on control days and 599 on intervention days. There was no significant difference in total patient LOS: median = 273 minutes, interquartile range (IQR) 176 to 384 minutes on intervention days versus median = 253 minutes, IQR = 175 to 365 minutes on control days (p = 0.20). There was no difference in left-without-being-seen (LWBS) rates (n = 48, 7% on control days vs. n = 35, 6% on intervention days; p=0.38). Secondary analysis of only ESI 3 patients showed no difference in total LOS between periods (median = 284 minutes, IQR = 194 to 396 minutes on intervention days vs. median = 290 minutes, IQR = 217 to 397 minutes on control days; p = 0.22). There was, however, significantly greater total LOS for ESI 4 and 5 patients during the intervention period (median = 238 minutes, IQR = 124 to 350 minutes on intervention days vs. median = 192 minutes, IQR = 124 to 256 minutes on control days; p = 0.011). Conclusions The previously reported benefits on patient LOS and LWBS rates after adding a triage liaison (resource additive) were lost when that provider was moved from fast track to the triage role (resource neutral). While the triage liaison provider role may be a way to improve ED throughput when additional resources are available, as evidenced by our prior study, the triage liaison model itself does not appear to replace the staffing of treatment rooms, as evidenced by this study. © 2014 by the Society for Academic Emergency Medicine.