Kendall, 33, was batting .226 with two homers in 80 games with the Athletics. He'll be back in the National League, where he starred for the Pittsburgh Pirates from 1996-2004.
"This gives Jason, whom I have nothing but respect for, a chance to go somewhere he can play every day -- and play for a very good team with a good chance of making the playoffs," A's general manager Billy Beane said.
Gary Hughes, a special assistant to Hendry, had recommended getting Kendall, who was hitting .297 in his last 25 games, and batted .286 in Interleague Play this year.
"I'm sure he's not quite the offensive force he was four, five years ago, but we felt that behind the plate, he was a real good fit for us," Hendry said.
When the season began, Michael Barrett and Henry Blanco were the Cubs' catchers, but Barrett was dealt to the San Diego Padres on June 20 in exchange for Bowen, because the team wanted to improve defensively behind the plate. Blanco has been sidelined since May 31 with a herniated disk in his neck.
On Friday, the Cubs called up Geovany Soto, who was hitting .341 at Triple-A Iowa, and also have Koyie Hill on the roster. Hill started Monday's game batting .148 but did hit his second homer of the season leading off the second inning.
"We're just really, really happy to add Jason to the club," Hendry said. "He's a guy we've always admired and respected. We think he's a perfect fit for us in the second-half race. His character and leadership is terrific. He's an outstanding catcher, and he's still got a lot left in the tank."
"We're just really, really happy to add Jason [Kendall] to the club. He's a guy we've always admired and respected. We think he's a perfect fit for us in the second-half race."
-- Jim Hendry
The A's will miss Kendall.
"To not acknoweldge his impact on the pitching staff would be foolish," Beane said. "I think the people of Chicago will really identify with a guy like Jason."
"He's one of the most professional guys I've ever come across," said Oakland outfielder Mark Kotsay. "Just the epitome of what a player and teammate should be. But this is probably a good thing for Jason. He's had a lot of success in the [NL] Central. He had the best years of his career in that division, and I'm sure he'll be able to give them a big boost in what they're trying to do."
Bowen may have been pressing since joining the Cubs in June.
"Like I told Rob, he didn't do anything wrong," Hendry said. "When you get a chance to acquire Jason Kendall, you move forward.
"I had no intention of trading Rob Bowen a week ago. Things just happened," he said.
Kendall, a three-time All-Star who reached the postseason last year with Oakland, may provide both stability and experience behind the plate.
"He's a gamer, he's a high character guy," Hendry said. "He's a great handler of pitchers, he's a 10 in the clubhouse and a guy who wants to win every day. He's exactly what you want character-wise as you go down the stretch."
Blevins, a 6-foot-6 left-hander, was 3-2 with a 1.02 ERA for Class A Daytona and Double-A Tennessee this year, appearing in 38 games.