Hairston was hitting .327 with eight home runs and 23 RBIs, including a .379 average in 58 at-bats against left-handed pitchers. He was leading the team in batting average and was second to Gonzalez in home runs and RBIs at the time of his injury.
"No doubt, Scotty was productive from early in the season. When he got the at-bats and consistent starts, he continued that," San Diego manager Bud Black said. "We're hoping that he can pick up where he left off."
With the Padres facing four left-handed pitchers in the next six games, Hairston's return couldn't have come at a better time for a team that is struggling mightily against lefties, as San Diego is hitting .219 against southpaws.
Hairston, who was in the starting lineup in center field Tuesday and hitting third in front of Gonzalez, could provide some right-handed production the team has lacked and could also protect Gonzalez, who has walked 26 times in June, 21 times in the 16 games that Hairston has missed.
Hairston pronounced himself fit and ready to play Tuesday after playing three weekend games with Class A Lake Elsinore, where he was 1-for-10.
"I went down there for three games and made a lot of strides," Hairston said. "The way I felt after the third game, I was ready to come back. It felt great, the body felt great, the biceps ... I had no problems with it."
Hairston suffered the injury swinging the bat in his second at-bat in a 10-5 loss on June 2 against the Philadelphia Phillies. He did his rehabilitation in San Diego before heading on what quailed as a short rehabilitation assignment.
"I think the main thing was how my biceps was going to react to playing, getting four or five at-bats a game. The last game I got six at-bats. It took me a couple of days to get my timing down. My swing felt great, my balance was good at the plate. There were a lot of balls that I swung at I was way out in front of and hit foul," Hairston said.
"In my case I wanted to get enough swings when I was down there to test it out. All three days I was working on something different. The first day I was working on seeing pitches. The second day was really trying to be more aggressive swinging the bat. The third day was the way I would approach a game like today if I wasn't rehabbing."
As for Giles, he was placed on the DL retroactive to Friday with a right knee contusion, an injury he suffered a week ago Tuesday when he jammed the knee on the base paths in a game against the Mariners.
Giles, who is hitting .191, said "it's the same scenario as two years ago" when he injured the knee in May and missed 34 games.
"It's a little bit of the same feeling he had a couple of years ago. He tried to play through it and eventually went on the DL," Black said. "We tried to get this early and let it quiet down. We were hoping there would be some improvement, but there hasn't been a great deal of improvement."