"I'm expecting the worst," Gwynn said. "I'll have the Dodger uniform on. I don't think the last name on the back really matters at that point."
He shares his name with his father, Tony Gwynn Sr., the most beloved player in the history of the Padres' franchise and a Hall of Famer who accumulated 3,141 hits over a 20-year career.
Having spent a significant part of his youth in the clubhouse with his father, Gwynn Jr. is intimately familiar with the Dodgers-Padres rivalry. Gwynn Jr.'s uncle, Chris Gwynn, played for the Dodgers from 1987-91 and 1994-95 and for the Padres in 1996.
"With my dad playing for the Pads, I was rooting against [the Dodgers] all the time," Gwynn Jr. said. "There were times my uncle wasn't playing and I was upset about him not playing, so it just gave me a little more fire to root against them."
Gwynn Jr. said he gained a greater appreciation for the rivalry in 1996, when the Padres beat out the Dodgers for the National League West title. The Padres swept the Dodgers in Los Angeles in the final series of the season to finish a game ahead in the standings. The Padres won the final game on a two-run, pinch-hit double by Chris Gwynn.
"From that point on, I started to understand how serious that rivalry was," Gwynn Jr. said.
However, Gwynn Jr. still had a soft spot for the Dodgers' cap, and as a teenager that got him in trouble with a certain record-setting Padres closer.
"I remember a couple of times Trevor Hoffman taking my hat away from me when I was in the clubhouse," Gwynn Jr. said. "It was different colors, but it was an L.A. hat … From that point on, I never wore it again."
Gwynn Jr. said there weren't any down sides to growing up in the town his famous father worked. "I never looked at it as pressure," Gwynn Jr. said.
Others tried to protect him from the inevitable comparisons.
In his first game at San Diego State, he was introduced as Tony Gwynn Jr. and didn't get a hit. After that game, then-Aztecs coach Jim Dietz, who also coached his father and uncle, told him he would be called Anthony from then on.
Gwynn Jr. played his final two years at San Diego State under his father, who has been the Aztecs' head coach since the fall of 2001.
Drafted by the Milwaukee Brewers in 2003, Gwynn Jr. was traded to the Padres six years later. He said moving to San Diego actually took pressure off him.
"People had seen me play since high school, college," said Gwynn, who starred at nearby Poway High. "I didn't have to worry about living up to my dad's legacy out there. I was able to do my own thing."
Just not for as long as he would have liked.
While advanced statistical measures indicate Gwynn Jr. was among the best defensive center fielders in baseball, his batting average dipped from .270 in 2009 to .204 last year.
With Gwynn Jr. eligible for salary arbitration for the first time, the Padres decided to cut ties with him instead of offering him a significant raise.
The Dodgers, who like what he adds defensively, picked him up on a one-year deal worth $675,000.
"I consider myself a man of faith and God had another plan for me regardless of how I felt about it," Gwynn Jr. said. "I think coming here was probably the best thing that could happen for me."