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7/14/2013 9:41 P.M. ET

Carter nursing sore ankle, sitting Sunday

ST. PETERSBURG -- Outfielder Chris Carter was out of the lineup Sunday and still feeling the effects of a sore ankle that he injured during Friday's game.

"He kind of tweaked his ankle a little bit [on Friday night] rounding third base," said Astros manager Bo Porter. Yesterday he got treatment and today, with the All-Star break coming up and us having a few more days, it just made sense to let him rest and come back on Friday."

Carter is hitting .229 with 18 home runs and 47 RBIs.

Porter confident in Astros' core of young players

ST. PETERSBURG -- Astros manager Bo Porter believes that his team can answer several questions about the future of the organization during the second half of the season. The Astros (33-60), will enter the All-Star break with the worst record in baseball regardless of the outcome of Sunday's game against the Rays.

Despite the numbers, Porter is optimistic that his young players will continue to develop and improve in the second half.

"We definitely want to capitalize and turn our goofed performances into wins," Porter said. "But more importantly, we want to continue to monitor the development of these players.

Porter can draw a handful of positives out of the first half of the season, and he's seeing a core of young players beginning to take shape. Jose Altuve's four-year extension shows that the organization is committed to the club's long-term success.

"I've said this for the entire time I've been here -- the most important aspect of any organization is to properly evaluate your players," Porter said. "You don't want to go into the offseason with the number of questions we had last year.

"We have answered a lot of questions [this season], because we've allowed guys the opportunity to go out and show us exactly what they are able to do at the Major League level."

Worth noting

• According to Porter, right hander Brett Oberholtzer was sent down to Oklahoma City after Sunday's game and a corresponding roster move will be made before Friday's game against Seattle. Oberholtzer was recalled on July 2 and only made two appearances. He has not pitched since July 5.

• Brett Wallace has been swinging a solid bat since being recalled from Triple-A Oklahoma City on June 25. The first baseman, who went 1-for-4 with a two-run homer on Saturday, is hitting .296 with four homers, four doubles and 13 RBIs since being called up.

• Porter did not commit to a rotation coming out of the All-Star break other than to say that Bud Norris will get the start on Friday against Seattle.

• Carlos Pena remained in the leadoff spot for Houston on Sunday. He went 1-for-3 with a walk on Saturday.

• The Astros will work out Thursday at Minute Maid Park following the All-Star Break. The workout is expected to be closed to the media.

Corey Long is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.