Gunners boss Arsene Wenger, though, questioned why Walcott was included in the Under-21's European Championship campaign last summer, where the young Lions reached the final.
Pearce, however, insists Walcott will have become a better player for the experience - and any subsequent fitness problems were an issue for Arsenal, rather than the national squad.
"I don't agree with Arsene at all," Pearce told the London Evening Standard.
"He didn't play for long periods of last season, but he was fully fit at the end so he came with me to the Championships.
"It was a great experience and his first participation in a major international tournament, but then he hasn't featured a great deal this year."
Pearce insisted: "When he left me he was fully fit. I can't be responsible for him picking up an injury at Arsenal.
"Most of the injuries Theo has picked up have come while playing for his club so I don't really understand where Arsene is coming from.
"Theo has not been over-extended in playing too many games.
"Two years ago, when Theo played every match for the Under-21s, it built his confidence up when he wasn't playing so well for Arsenal, they benefited and I didn't hear him [Wenger] complain then."
Pearce, though, believes Walcott has what it takes to make Fabio Capello's World Cup squad.
"It has been a bit stop and start for Theo to say the least," the former Manchester City boss said.
"He played extremely well against Sunderland and will be aware now that he has got to stay injury free and get a run of form together when playing for Arsenal, then he will get in the squad for South Africa and that should be his target."