PHOENIX — Arizona starter Dan Haren had a simple two-word answer when a visitor asked him Tuesday whether he was looking forward to his scheduled appearance tonight against his old teammates.

"Of course," he said.

Seems it was a rather obvious answer to a rather obvious question. Haren, the central figure in an eight-player deal between the Diamondbacks and A's in December, said he has been looking forward to this series since the trade was made.

Hard to imagine his former club has felt the same way.

"It'll be exciting, and a little weird," A's second baseman Mark Ellis said. "It's always strange when you face somebody you played with, but that's how it is around here. Guys come and go. It's part of the game, especially for this organization."

Haren, who won 43 games and posted a 3.64 ERA in three seasons for the A's, has flashed a similar form in his first campaign with Arizona. He has gone 6-4 with a 3.41 ERA in 14 starts, and his 892/3 innings trail only Tuesday's starter Brandon Webb among Arizona starters.

"It's been great," Haren said. "The guys are great, it's a class organization. Everything has been first-rate. No complaints."

Following Webb in the rotation has been a nice bonus, too, he said.

"I can't help but benefit from that," he said. "It makes it easier in that it takes a lot of pressure off. I've been in rotations with great pitchers before, in Oakland with (Barry) Zito and in St. Louis with (Chris) Carpenter, and it's nothing different here. (Webb)'s a great pitcher, and to watch him every day, if you can't take something from it, then you're just not paying attention."

Ellis' hot spell

Ellis was in the leadoff slot for the fourth straight game, a development at least partially stemming from a typical June hot streak. Ellis, a career .294 hitter in the month, was 13-for-31 (.419) with four doubles, a home run, six RBI, seven runs and five multihit games in his past seven entering Tuesday's game. Overall, he was 17-for-55 (.309) in June, lifting his average to .256 from a low of .228 on May 29.

"I'm just terrible in April and May," he said. "Actually, I've felt pretty good all year except for a couple of weeks early on. Now, things are starting to pick up, and I'm finding some holes."

Short hops

Manager Bob Geren said reliever Santiago Casilla (elbow soreness) likely won't be activated until Thursday at the earliest. Casilla threw 12/3 innings and struck out four in a rehab assignment for Triple-A Sacramento on Monday and is with the team. "... Starting pitcher Trevor Cahill, the A's top selection in the 2006 draft, was promoted to Double-A Midland. He went 5-4 with a 2.78 ERA and was selected to the California League All-Star team while with Single-A Stockton.

— Rick Hurd