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7/13/2013 10:34 P.M. ET

Maxwell returns to Astros lineup

ST. PETERSBURG -- Starting center fielder Justin Maxwell returned the lineup and was sixth in the batting order on Saturday. Maxwell, who was on the seven-day disabled list due to concussion symptoms, played three games earlier this week at Triple-A Oklahoma City as part of his rehab assignment.

Astros manager Bo Porter was excited to have Maxwell back on the field, but expects he will need time to re-adjust to the speed of the game.

"I'm a firm believer that a guy doesn't lose his starting job due to injury," Porter said. "But I'm also conscious of the fact that he's missed a lot of time."

Maxwell is batting .235 entering Saturday's game with one home run and six RBIs.

Porter thrilled with Altuve's extension

ST. PETERSBURG -- Houston Astros manager Bo Porter was all smiles before Saturday's game against Tampa Bay as he spoke of the team's future with second baseman Jose Altuve. The Astros agreed to a four-year contract extension with the 23-year-old.

"It's a big day for our organization," Porter said. "Jose Altuve stands for everything we talk about as an organization. He's a great teammate, he leads by example, says the things that are necessary to say in the locker room and leads on the field."

Entering Saturday's game, Altuve leads all Major League second basemen in stolen bases (21) and double plays turned (74) and is hitting .280 with 15 doubles, a triple, three home runs and 28 RBIs.

"He's one of the best hitters in the league, and I'm happy he's going to be here for a long time," Porter added.

Pena fills leadoff role at familiar ballpark

ST. PETERSBURG -- Carlos Pena hit first for Houston on Saturday at a ballpark where he had some of his best moments. Pena, who played five seasons with the Rays (2007-2010, 2012), is the all-time home run leader at Tropicana Field, where he has hit 86 jacks.

"I have so many great memories of this building," said Pena. "The best years of my career were here."

This was Pena's first time leading off for the Astros, and he was the designated hitter. Entering Saturday's game, he was batting .213 with eight home runs and an OBP of .327.

"One of the things I like about Bo [Porter] -- he's not afraid to try something new," Pena added. "The quantum leaps occur when you're not afraid to change."

After stellar debut, Cosart returns to Triple-A

ST. PETERSBURG -- Pitcher Jarred Cosart returned to Triple-A Oklahoma City on Saturday, but the countdown for his return to Houston is on.

Cosart held the Rays scoreless and surrendered only two hits over eight-plus innings for a victory in his Major League debut on Friday. He became the first pitcher in Astros history to toss eight-plus scoreless innings in a Major League debut.

Cosart was sent down so he could stay on his regular pitching schedule during the All-Star break. Astros manager Bo Porter said the organization would discuss plans for the second-half rotation during the time off.

"Jarred Cosart was high on our chart long before he made his start last night," Porter said. "It gives us more confidence he has the ability to be in the front of our rotation for a long time."

Worth noting

• The Astros announced the signing of their 11th-round Draft pick, pitcher Devonte German. The right-hander was signed before Friday's 5 p.m. deadline. The Astros signed 32 of their 40 draft picks this season, including all of the their top 10 selections.

• Three prospects will be representing the Astros organization in Sunday's SiriusXM All-Star Futures Game. Second baseman Delino DeShields and outfielder George Springer will be playing for Team USA, while shortstop Carlos Correa will be playing for the World Team.

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