Panik on concussion DL

MIAMI — After he got hit on the head Sunday in Washington, Joe Panik was cautiously optimistic. On Monday, he was more cautious.

On Tuesday, the optimism was gone. Panik’s condition had worsened, and he was placed on the seven-day concussion disabled list.

Manager Bruce Bochy said Panik was “not feeling great.”

Panik took a blow to the head in Washington when he slid into the plate and was hit by a ball thrown by center fielder Michael Taylor just as catcher Matt Wieters caught it and tagged him.

It’s the second time in two years that concussion symptoms have shelved the second baseman. He missed a month last season and said he didn’t recover until the offseason.

The Giants replaced Panik on the roster with utilityman Orlando Calixte. Tuesday’s second baseman was Kelby Tomlinson, and Miguel Gomez will be an option when he comes off the disabled list.

Brandon Belt, who’s also on the concussion DL, will be re-examined Wednesday. Bochy said the first baseman has experienced no improvement.

Melancon’s role: Bochy wouldn’t say when Mark Melancon would return to the closer’s role. Melancon made his second appearance since coming off the DL and pitched a scoreless seventh inning.

Melancon was shelved with a pronator strain, and Bochy said it remains a bit of an issue. Asked how close Melancon is to closing games, Bochy said, “I don’t want to say how close. We’ll see how he bounces back and responds. I’m aware of two things, his situation and getting in the flow of things, and Sammy (Dyson) throwing the ball well, which allows us to take it easy with Mark right now.”

Briefly: Bochy asked Pablo Sandoval about resting Wednesday, but Sandoval objected. ... The Giants held out hope of signing pitcher Jack Conlon, the Orioles’ fourth-round pick who became a free agent after he failed a physical. Conlon is set to attend Texas A&M.

John Shea is The San Francisco Chronicle’s national baseball writer.