Padalecki's on-screen brother did eventually find his way into The CW series about the Texas Ranger, but not in the capacity he could have.
"When I started developing 'Walker'... unbeknownst to him, but my pitch was that Jensen was going to be Walker," Jared laughed, when speaking to Michael Rosenbaum on his podcast 'Inside of You'.
Among the reasons Jared had in mind were that Jensen lives in Texas, is a good actor and likes riding horses. Apparently, Padalecki was ready to pitch the idea to The CW even without actually getting a green light from Jensen.
Despite Jared ended up starring in the series, he initially had no intention to do it, only willing to take control of the show's creative part: essentially, to only be exec producing.
It's unclear whether Jensen was ever aware that Jared considered him for the role of the Texas ranger. However, the 'Supernatural' alum did direct one of the episodes, titled 'No Such Thing as Fair Game', and even made a secret appearance at some point – never stepping out of the shadows, however.
Currently, 'Walker' has two seasons, and the network has recently greenlit a prequel, titled 'Walker: Independence', with the release date yet unscheduled.