Boxberger, a right-handed reliever, was promoted from Triple-A Tucson on Monday to take the place of reliever Joe Thatcher, who landed on the 15-day disabled list with tendinitis in his right knee.
Boxberger didn't just come to Cincinnati looking different, but he feels he's a much better pitcher than he was in June, when he walked seven in 6 1/3 innings in five games before heading back to Tucson.
"[Padres pitching coach Darren Balsley] and I talked about a couple of mechanical things, but I've been attacking hitters more and going after hitters earlier in the count," Boxberger said.
"It was too many [walks], so I'm definitely trying to cut those down this time around."
In 10 appearances in July with Tucson, Boxberger was 1-0 with a 0.77 ERA in 11 2/3 innings. Not only did he strike out 17 in that stretch, but he walked only three batters.
"Getting sent down isn't fun, but coming back this time, I know what to expect," said Boxberger, who has a 2-2 record and a 3.03 ERA in 34 games for Tucson.
That's a lesson manager Bud Black is hoping many of the young relievers who have been on the roster at varying times this season -- Miles Mikolas, Brad Brach, Nick Vincent -- have embraced: Go down, pitch better, come back to the big leagues better prepared.
"We've seen guys go back and come up, go back and come up and they're incrementally better," Black said
The reports from Tucson manager Terry Kennedy on Boxberger were good, Black said.
"He was throwing the ball extremely well in Tucson, so hopefully there's a carryover," Black said.
As for Thatcher, his balky right knee just hasn't responded to treatment enough in the last few days for the team to be shorthanded in the bullpen any longer.
"He just couldn't get over the hump with the knee," Black said. "This was the right thing to do."