Jarvis has made four appearances out of the bullpen for the D-Backs so far this season, with his most recent one coming on June 11 when he gave up six earned runs in 1 2/3 innings against the Mets. He does not have a decision on the year and holds an ERA just under 10.
"With eight guys down there in the bullpen right now we feel like we're in good enough shape where we can bring somebody out of the bullpen, try to get five innings or so out of him and then bring in the rest of the guys," Melvin said.
"It's kind of dictated by the flow of the game, but my arm strength feels pretty strong so I'm not too worried about pitch counts and things like that," Jarvis said.
Jarvis was called up from Tucson on May 20 and went 2-5 in nine starts with a 3.64 ERA for the Sidewinders.
With right-handed starter Juan Cruz throwing a bullpen session on Thursday, Melvin said Saturday's game will be a spot start for Jarvis and that Cruz could be ready to return to the rotation on June 22. Cruz has been on the disabled list since June 7 with a sore right shoulder.
Just in time: After being recalled from Tucson on Tuesday, left-handed reliever Randy Choate arrived to Chase Field shortly before the first pitch at 6:40 p.m.
"[I got here] at 6:30. I walked in, I took a shower, I changed in my clothes and walked out with [Brandon] Lyon at the last minute.
"I was telling somebody yesterday that you appreciate it a lot more when you've been gone for so long," Choate said. "I guess I don't know how I would really put it into words."
He collected a 3-0 record with a 2.45 ERA in 32 appearances for Tucson this season and was used eight times out of the bullpen last season by the D-Backs.
Choate admitted that it is at times discouraging to be playing well in Triple-A without getting the call from the big league club.
"It was discouraging at times because I thought I was pitching good enough to be here. I wasn't getting the call and other guys were pitching well too and they got the call before and sometimes it's discouraging when you feel you're doing everything you can and everything they've asked and you don't get it," he said. "I had a talk with [general manger] Josh [Byrnes] earlier in the year and he said just be patient, you're definitely in our plans."
With the exception of Terry Mulholland, who is currently on the disabled list, Choate provides the only left-handed arm in the Arizona bullpen.
On a roll: The Sidewinders have been on a tear of late, having won 10 straight games to put them in first place of the South Division in the Pacific Coast League with a 3 1/2-game cushion.
"They're on one of those rolls where you just feel like you're invincible every time you go out there no matter who's starting," Melvin said. "It's a day if pitching's there, the offense does enough. If the pitching's not there, the offense does a bunch. It seems like all those guys are swinging the bat well."
More signings: The D-Backs signed four more names from last week's First-Year Player Draft.
Right-hander Daniel Stange (seventh round), third baseman Andrew Fie (12th round), infielder Matthew Oxendine (15th round) and catcher Roberto Cruz Jr. (34th round) have been assigned to the D-Backs rookie ball affiliate, the Missoula Osprey.
Up next: The D-Backs conclude their three-game series with the Giants on Thursday at 3:40 p.m. MST.
Right-hander Miguel Batista (6-3, 4.69 ERA) will take the mound against the Giants' Matt Morris (3-7, 5.13 ERA).