"He realizes he made mistakes, and I applaud that," Hall said to reporters at the club's Celebrity Golf Classic on Friday. "That shows a tremendous amount of maturity on his part."
Last season, Bauer went 12-2 with a 2.42 ERA and 157 strikeouts in 130 1/3 innings in the Minor Leagues, and 1-2 with a 6.06 ERA, 17 strikeouts and 13 walks in four starts for the D-backs. But the club's first pick in the 2011 First-Year Player Draft raised eyebrows with what appeared to be an unwillingness to adapt his style of pitching to big league hitters and poor communication with veteran catcher Miguel Montero.
According to Hall, Bauer has already reached out to several of his D-backs teammates -- including veteran J.J. Putz -- this offseason. The pitcher has also spoken with members of the front office in an effort to mend fences with the organization.
"This season, although it was not good for him at the big league level, it was at the Minor League level," Hall said. "At the big league level, it was probably the most important season, because it was his biggest learning lesson in his life. What we have heard from him lately is very encouraging. He realizes he has made mistakes and he wants to embrace his teammates and hopes that they forgive him. Just really positive signs and we see a lot of maturity from everything he went through."
Hall said he understand why some clubs might believe Bauer is on the trade market.
"Teams are assuming after the bumpy start that Trevor had that we may be looking to move him, and we are not. We are not shopping him," Hall said. "Again, if they ask, [GM Kevin Towers'] response is 'Hey, we are willing to listen,' and that's what's happened here. Trevor has a bright future."
Addressing another trade rumor, Hall said that it's too early to tell if outfielder Justin Upton will be moved this offseason. Upton is due to make $9.75 million next year, $14.25 million in 2014 and $14.5 million in '15.
"The great thing about Justin is that he's been through this a couple of years, so he really expects it," Hall said. "If nothing happens and he's still in a D-backs' uniform, we will be fine. It's all part of the game. I think he's so mature now to when he first entered the league. If this had happened back then, maybe he would react differently, but he handles it so well and it's not an issue."
According to reports, the D-backs would need an everyday position player or top-of-the-rotation pitcher in return as part of a deal for Upton.
"It's not about Justin. It's not like we are shopping him," Hall continued. "We are willing to listen to anybody, and we've always said that. I think what happens is that if opposing GMs talk to Kevin or anybody on our staff and say, 'Hey, are you willing to talk about Justin?' and we say 'Yes,' -- to the media it's, 'Hey, they are willing to talk Justin,' and there it goes and it spirals out of control."