Making his second start in place of second baseman Dan Uggla, Tyler Pastornicky had to leave Wednesday’s game in the fourth inning with a sprained left knee after colliding with right fielder Jason Heyward.

The Braves are holding out hope the injury isn’t serious. Pastornicky was scheduled to undergo an MRI on Thursday to find out the extent of it. The Braves were not expected to update his condition until Friday.

“All the news I’ve heard so far is good,” said Pastornicky who was standing at his locker after Wednesday’s game, wearing a wrap on his knee underneath his jeans. “They did all the tests on it and the tests all came out all right, but still do the MRI tomorrow and see where it goes from there.”

Pastornicky was called up from Triple-A Gwinnett on Tuesday afternoon when the Braves put Uggla on the disabled list in preparation to undergo Lasik eye surgery.

Braves general manager Frank Wren said at the time that Uggla’s situation didn’t change the Braves plans for how they’re approaching the waiver trade market. The Braves are hoping to add a backup infielder and left-handed bat before Aug. 31. That search could intensify depending on the severity of Pastornicky’s injury.

The Braves played the remainder of Wednesday’s game without another middle infielder. Manager Fredi Gonzalez said Joey Terdoslavich could have played one of the corner infield positions but if either Andrelton Simmons or Paul Janish had gotten hurt, he might have had to put center fielder B.J. Upton at shortstop.

“B.J. (Upton) came up as a shortstop; I’m sure he’d love to play the middle infield,” Gonzalez said. “I’m glad that didn’t happen.”

For now the Braves are hoping with the off day Thursday, and possibly covering for him on Friday too, Pastornicky will be able to return over the weekend without them having to make another roster move. If they have to DL Pastornicky, though, they are likely to turn to Tommy La Stella. The 2011 eighth round pick out of Coastal Carolina is hitting .339 (77-for-227) in Double-A Mississippi.

Pastornicky collided with Heyward trying to catch a Jimmy Rollins fly ball in the third inning. He was able to get up on his own and play the rest of the inning but left the game after his knee tightened up leaving the field.

Both Heyward and Pastornicky said afterward they were calling for the ball. Gonzalez said he could hear Heyward calling for it all the way from the dugout, but Pastornicky said he didn’t hear it.

“I didn’t really know what happened because I was trying to catch the ball and it all happened so fast,” Pastornicky said. “I heard nothing. It’s one of those converging plays. I tried to yell as loud as I could but I think he was running in and kind of met at the same time.”

Heyward said he started calling for the ball really early and continued to call for is as he approached Pastornicky.

“Sometimes the crowd gets in the way of that when somebody is going hard…” Heyward said. “Tyler was going after it. Apparently he was calling it too so. It just happens sometimes. Unfortunately he had to come out of the game.”

Gonzalez had wanted to rest Simmons Wednesday night after playing 29 consecutive games at shortstop, but Gonzalez had to insert Simmons at shortstop and move Janish to second base when Pastornicky left the game.