Bradford detailed in a text that he was willing to help Rosen with whatever he needs, a nice gesture considering the latter is being groomed to take his job.
Rosen, who was the 10th overall pick in the 2018 NFL Draft, joined his parents and agent in being driven toward his introductory press conference in Tempe (Ariz.) before receiving a text, according to the Cardinals' "Flight Plan" series on the team's website.
"Sam just texted me ... Bradford," Rosen told agent Ryan Williams.
"He said, 'Josh, what's up, man? Welcome to Arizona. Just wanted to let you know that I look forward to playing with you. I'll be an open book, so if you ever need anything or have any questions, feel free to ask. Hope all is well.'"
Rosen was quick to text back to Bradford before addressing the media for his press conference.
"First and foremost, I'm an Arizona Cardinal. It's team before everything. ... I'm going to compete my butt off every single day, but then again, I'm not going to be the guy that comes in and thinks he's the man from Day 1. It's a long process, and you've got to earn it."
Rosen passed for 9,301 yards and 59 touchdowns with 26 interceptions while playing in 30 games in three seasons as UCLA's starting quarterback.
This past season, Rosen passed for 3,754 yards and 26 touchdowns with 10 interceptions as UCLA finished with a disappointing 6-7 record. He did not play in the Bruins' 35-17 Cactus Bowl loss to Kansas State while recovering from a concussion.
Bradford initially was slated to guide the team after signing a one-year, $20 million contract in March. The oft-injured Bradford appeared in just two games with the Minnesota Vikings in 2017. He went on injured reserve and had arthroscopic surgery in November before being activated as Case Keenum's backup during the postseason.
A former Heisman Trophy winner and top overall pick of the 2010 NFL Draft, Bradford has thrown for 19,049 yards with 101 touchdowns and 57 interceptions in 80 career contests with the then-St. Louis Rams, Philadelphia Eagles and Vikings.