Manager Bob Melvin said that Claudio Vargas would pitch out of the bullpen on Wednesday, if necessary. Melvin added that a decision as to which starting pitcher will be leaving the rotation to accommodate Hernandez will be announced after Thursday's off-day.
"We need Vargas available in the bullpen [Wednesday]," Melvin said. "With Bajenaru going down, we have a six-man 'pen right now."
If Vargas is not used Wednesday, he could be a candidate to start on Monday. The D-Backs have not yet determined their rotation beyond this weekend. Vargas last pitched on Sunday, earning the win after giving up two runs on six hits over six innings.
Hernandez, who threw a bullpen session on Wednesday, is scheduled to start on Friday against the Marlins, giving Brandon Webb another day of rest before he throws on Saturday. Webb missed his last start on Saturday due to tightness in his forearm just below his right elbow. Rookie right-hander Enrique Gonzalez will pitch the series finale against Florida on Sunday.
Here's Johnny: After visiting with a gastrointestinal specialist on Wednesday, it appears that Johnny Estrada may have a stomach ulcer. Another test, which involves sedating the catcher and placing a scope down his throat to check out his stomach, needs to be completed until he can know for sure that an ulcer is the root of his nausea problems, which have been plaguing him since last week in Chicago.
Estrada was a late scratch from Tuesday's lineup, but he did start on Wednesday.
He said he would probably wait to have the other test because he doesn't want to miss anymore playing time.
"In the morning, [the nausea is] really bad," said Estrada, who is a candidate for the Comeback Award. "But they've been giving me medicine, and the doctor just doubled my dose to take. If it's 100 percent sure that I have an ulcer, there's nothing really they can do except give me medicine. There's nothing that's going to make it go away tomorrow.
"I'll just try to deal with it -- hopefully keep it in check."
Green to go: Infielder Andy Green (shoulder) is scheduled to begin a injury-rehabilitation assignment on Saturday with Triple-A Tucson.
Green will likely spend the entire 20 days allowed for a rehab assignment down in Tucson, as it will be easier to clear a roster spot for him after Sept. 1 when the rosters expand.
"I'm just anxious to get back on the field," Green said. "I want to help this team out any way I can in September."
Injury update: Melvin said that Jeff DaVanon, who rolled his left ankle when sliding into second base on Saturday, was available to pinch-hit on Wednesday. Conor Jackson, who was hit by a Jason Schmidt pitch on Monday, could also be used as a pinch-hitter.
Shortstop Craig Counsell, who was placed on the 15-day disabled list on July 15 with a fractured right rib, took swings with the group during batting practice for the first time on Wednesday.
First baseman Tony Clark threw out to 100 feet on Wednesday. Clark has been on the disabled list since July 18 with right shoulder inflammation. Melvin said he wants Clark to throw 120 feet before he makes a Minor League rehab appearance.
"Whether it's early in the next road trip or whatever, we're starting to get to a point where we're looking at some days, but [we're] not certain [yet]," Melvin said of Clark and Counsell. "They need to get some live at-bats."
Back to Tucson: Left-handed specialist Randy Choate, who was designated for assignment on Sunday, cleared waivers and accepted his assignment to Tucson. Reliever Mike Koplove, who was designated on Saturday, cleared waivers and was optioned to Tucson. Koplove remains on the 40-man roster.
Up next: After an off-day on Thursday, the D-Backs open up a three-game series with the Marlins on Friday at 6:40 p.m. MST. Hernandez will make his Diamondbacks debut, and he will be opposed by Josh Johnson, who holds the second lowest ERA in the National League behind Webb.