Simple Summary The genus Salsola comprises salt-tolerant plants with a potential use as livestock fodder in arid regions. However, there is a lack of studies that characterize this potential utility of Salsola spp. In this study, Rambouillet lambs were fed Salsola tragus as a forage source to determine its effects during the fattening phase on lamb growth, in vitro dry matter degradability, gas production, carcass quality, and cellular damage from oxidative stress during the fattening phase, while also determining its impact on the metabolomic meat interaction in lambs. Overall, the use of Salsola tragus as a source of forage in arid regions for lambs during the fattening period is promising due to its positive impact on meat metabolites without inhibiting lamb growth performance and carcass quality. The aims of the current study were to characterize the natural compounds of Salsola tragus via GC-MS and determine its effects as a forage source on lamb growth, in vitro rumen fermentation kinetics, carcass quality, cellular damage, and metabolomic meat interaction. Twenty-one Rambouillet lambs were randomly assigned to one of three experimental diets (seven lambs per treatment): (1) a control diet (W/o-Salsola) containing 300 g/kg dry matter (DM) of sorghum stover; (2) a diet with a medium inclusion of Salsola tragus (15-Salsola), which contained 150 g/kg DM of Salsola tragus and 150 g/kg DM of sorghum stover; and (3) a diet comprising 300 g/kg of Salsola tragus (30-Salsola). The results showed there were no differences (p > 0.05) in lamb growth performance during the fattening phase. The in vitro gas analysis demonstrated that the 30-Salsola treatment increased lag time h(-1) (p < 0.05) and reduced gas production (p = 0.03). The metabolomic analysis findings suggest that the treatments that included Salsola tragus significantly positively affect the metabolomic composition of meat (p < 0.05). The use of 15-Salsola as a source of forage is promising for feeding lambs during the fattening phase.