Ronnie Gardocki's relationship with Shane Vendrell is much more antagonistic. For the first few seasons they were shown to be good friends, albeit not as close as Shane was to the other two. This is evident in a Season One episode when Lem and Shane profit $10000 each from a cockfighting ring, and Vendrell gives $5000 to Mackey, when Lem asks about Gardocki, Vendrell simply says "Screw Ronnie! He is off the clock". Later episodes would reveal that Vendrell considered Gardocki to be Mackey's "whipping boy", due to the fact that Mackey often has Gardocki run errands and leaves him out of major decisions involving the Strike Team. Despite this, Vendrell was visibly annoyed and upset when Tavon Garris momentarily replaced Gardocki after the latter's hospitalization, though in the end Gardocki returned and Garris also stayed.
During the events leading to the Strike Team's temporary dissolution, Gardocki became privy to several of Vendrell's misdeeds. When $7000 of the Money Train cash went missing, Garocki suspected Vendrell and chastised Mackey for not suspecting Vendrell sooner. He comes to see Vendrell as a liability who must be watched in case he does anything which could implicate the team members in any wrongdoing. When gang leader Antwon Mitchell orders Vendrell to kill Mackey, Gardocki tells Lemansky that he hopes Mackey kills Vendrell during their next meeting.
Their friendship heals to an extent when the Strike Team re-forms. He is more willing to accept Vendrell back into the fold than Lemansky. However, after he discovers that Vendrell killed Lemansky and then drafted up a document detailing the team's crimes as part of his scheme to protect himself from reprisals of Mackey, their friendship ends once and for all. Vendrell tries to lure Gardocki away from Mackey's side, but Gardocki remains angry at Vendrell, refusing to betray Mackey or even engage in small talk with when the two are forced to work together on a stakeout.
Gardocki eventually pushes Mackey to deal with Vendrell "once and for all," culminating in Mackey arranging for Vendrell to be murdered along with the leaders of the Armenian Mob. However, when Vendrell informs Mackey that he would be willing to transfer to a new precinct once they cleared themselves of the problems involving the Armenians, Mackey begins having second thoughts about the murder attempt. Vendrell survives the attempt on his life and realizes that Gardocki and Mackey had tried to kill him, leading to Vendrell arranging for Gardocki to be killed, a scheme that fails as well. When he and his family goes on the run, Gardocki fears that if caught they will testify against him and Vic to receive better deals. Despite their antagonism, Gardocki shows a deal of sadness when he discovers that Vendrell killed himself and his family, but at the same time shows relief thinking he is safe from prosecution, not knowing Vic already gave up Ronnie.