Iannetta spent a little more than a week on the concussion list, and he has not shown any hesitation in the batter's box since his return. He doesn't anticipate that changing if he should have to face Barbato in this series.
"It's just another at-bat," Iannetta said of a possible matchup.
Walker set for sim game
D-backs right-hander Taijuan Walker, who is on the disabled list with a blister on his right index finger, will throw a simulated game at PNC Park on Tuesday afternoon.
If all goes well, Walker could find himself starting the D-backs' series finale in Miami on Sunday.
"We haven't thrown out a road map as of right now other than getting him through tomorrow, and then we'll piece together how he feels," Arizona manager Torey Lovullo said.
Even if Walker is ready to pitch Sunday, the D-backs are still going to need a starter Saturday in Miami. It's possible that reliever Randall Delgado, who has started twice in place of Walker, could get another start, or Arizona could call up a pitcher from the Minor Leagues.
McFarland getting it done
Left-handed reliever T.J. McFarland has not given up an earned run in eight of his past nine outings, and he has allowed just one earned run in his 11 2/3 innings this year.
"I'm just throwing strikes, getting ground balls," McFarland said. "We've got an incredible defense, so it makes it a lot easier for the pitcher, especially me being a sinkerball guy. Getting ground balls, throwing strikes, getting ahead in the count. That's kind of the name of the game for me."
McFarland, 27, struggled last year with the Orioles, compiling a 6.93 ERA. He was released by the O's on Feb. 26 and signed to a Minor League deal by the D-backs on March 3.
"I had some injuries, dealt with some stuff, and then plain old had a bad year," McFarland said. "It's one of things where you try to forget about it and move forward. I kind of found a little bit of a rhythm, a little bit of a groove right now. Hopefully I can keep that going."
Steve Gilbert has covered the D-backs for MLB.com since 2001. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.