This invention is based upon the unexpected discovery that alkylated diphenylamines can be used in conjunction with nickel based catalyst systems which contain (a) an organonickel compound, (b) an organoaluminum compound, and (c) a fluorine containing compound to produce cis-1,4-polybutadiene having reduced molecular weight and an increased level of branching. This results in the cis-1,4-polybutadiene exhibiting good processability without sacrificing cold flow characteristics. Additionally, the alkylated diphenylamine which remains in the rubber acts in a manner which provides it with antioxidant protection. In other words, the use of alkylated diphenylamines accomplishes the three major objectives that are realized by employing para-styrenated diphenylamines (reduced molecular weight, regulated polymer macrostructure through branching and antidegradant protection). However, the utilization of alkylated diphenylamines, unlike para-styrenated diphenylamines, offers the additional advantage of being soluble in aliphatic solvents. By virtue of this increased level of solubility in aliphatic solvents, such as hexane, alkylated diphenylamines can be employed at greatly reduced levels of aromatic solvents. Likewise, when mixed catalyst streams containing alkylated diphenyl amines are combined precipitation is minimized compared to para-styrenated diphenylamine significantly improving issues related to fouling. The subject invention more specifically discloses a process for producing cis-1,4-polybutadiene having a reduced molecular weight and improved processability which comprises polymerizing 1,3-butadiene in the presence of (a) an organonickel compound, (b) an organoaluminum compound, (c) a fluorine containing compound, and (d) an alkylated diphenylamine; wherein the alkylated diphenylamine has alkyl groups that contain from 2 to 18 carbon atoms, and wherein the organoaluminum compound and the fluorine containing compound are brought together in the presence of the alkylated diphenylamine.