Marshall pitching with tight calf muscle

PHOENIX -- D-backs reliever Evan Marshall has been pitching with tightness in his right calf muscle, he confirmed to MLB.com prior to Saturday's rematch with Pirates at Chase Field.

Manager Chip Hale confirmed that Marshall had the nagging injury, which the right-hander sustained last weekend when the D-backs played the Giants in San Francisco, winning three of the four games.

"He had a little tight calf covering first, but that never stopped him from pitching," Hale said.

It was then noted that any physical malady could throw off a pitcher's mechanics.

"It might," Hale responded. "But he was actually pitching worse before he got that. I think the biggest effect is that he hasn't been able to do his running, and he has to do everything on a bike."

Yet in Marshall's last two outings this week against Texas and Pittsburgh, he faced 13 batters, allowing three earned runs, two hits and three walks in 2 2/3 innings.

For his part, Marshall didn't want to use the calf as an excuse, but it may be one reason why he's struggled during his first seven appearances of the season, logging a 7.71 ERA, a 2.14 WHIP (four walks and 11 hits) in seven innings. Opponents are hitting .355 against him.

"It's not really prohibiting me from doing anything except running," Marshall said. "It's straight forward movements where it gets a little tight. But driving off the mound it felt fine. I was able to proceed and just go out and keep attacking.

"It's something that I've been just nursing and taking care of in the training room, but it's not affecting me going out there, even as far as covering first base if I had to. I can get there."

Hale said that Marshall's problem has been pitching too high in the strike zone. He threw two innings during Friday night's 4-1 D-backs loss to the Bucs. Marshall came in down by two runs in the eighth inning.

After getting the first two hitters on grounders to short, Marshall walked Andrew McCutchen, who scored on Neil Walker's double. The Pirates scored all four runs in the game with two out.

"The only one that probably bothered me was the two-out walk of McCutchen by Marshall," Hale said after that game. "That was the only one that was a little bit bothersome. That one kind of hurt us because we had just scored a run and you want to shut them down. Other than that, I thought it was a step forward for Marshall. He hasn't located down well and he got a lot of ground balls [on Friday night], which is better."

Asked about Marshall's problems during his pregame media session on Saturday, Hale said: "The overthrowing part has been valid. His ball has been up. He's a sinkerball pitcher with a good changeup, so he's got to be down. I think he's gotten better. Last night it was good to get him a few innings and let him work on it. He's a work in progress."

Hale said right now right-hander Daniel Hudson would be used in the eighth inning to hold a lead with Addison Reed continuing to close.

David Hernandez, who two years ago had that eight-inning slot, continued his comeback from Tommy John surgery by throwing to four hitters at Salt River Fields on Saturday and is continuing to progress.

"We're tentatively thinking [Hernandez] could be back by the middle of May," Hale said.

Marshall, 25 and in his second year with the club, will just try to bring his numbers down.

"I hate looking up there and seeing a nine," said Marshall, referring to peering up at the scoreboard with his ERA up over 9.00 as was the case going into the game on Friday night. "What a relief it is to be below there and now all I can do is chip away at it."