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3/19/2014 10:58 P.M. ET

Castro ready for bigger workload behind plate

VIERA, Fla. -- Three years removed from reconstructive knee surgery, Astros All-Star catcher Jason Castro is prepared to carry an even bigger workload this year after missing most of September when he had to have a cyst drained in his surgically repaired knee.

Castro played in a career-high 120 games in 2013 and caught 98 games, which was a big jump over the 79 he caught in '12 in his first year back from surgery. The goal this season, Castro said, is to surpass 100 games behind the plate.

"I was feeling good all the way until the end of last year, when I kind of tweaked my knee stepping on a base," he said. "I felt great up until that point, and I don't see why I can't continue to push it even more. If I would have continued on that road, I would have ended with well over 100 games caught, and that's easily reachable this year. I don't see why I would any trouble getting past that."

Astros manager Bo Porter said he'll lean on Castro heavily, giving him days off behind the plate by slotting him as designated hitter and giving him day games off following night games.

"There are some times I'm going to take [playing time] out of his hands and there's other times … I'm going to check in with him and make sure we're staying on course as far as how his body feels," he said. "Catching every day in the big leagues is grueling, and if you don't map it out or get him to make it out, the guy could end up not being as productive as he's capable of being. It's definitely something that's a priority of ours, to make sure we keep that guy fresh."

Appel to make spring debut Friday

KISSIMMEE, Fla. -- Astros right-hander Mark Appel, who's spent most of the spring recovering from an appendectomy performed in January, is scheduled to appear in a game for the first time this spring. That will happen Friday, likely in a Minor League game and not the Grapefruit League game against the Marlins.

Appel, the No. 1 overall pick in last year's First-Year Player Draft, has been taking it slow since undergoing the procedure in Houston, just weeks before the start of camp. He said Wednesday he'll be prepared to throw an inning or two.

"I'm really excited," Appel said. "It's going to be good to actually toe the rubber in a Spring Training game. It's been a long time coming, so I'm real excited and grateful to have the opportunity to go out and compete with my teammates."

Manager Bo Porter said the decision on whether Appel pitches in the big league game or on the back fields has yet to be made, but he's anxious to see the big right-hander pitch.

"All things considered, if we don't have any hiccups between now and then, that is the plan," Porter said. "It will be great to see him get on the mound, and from an organizational standpoint, we have taken the precaution knowing it is Spring Training, and there's no sense rushing the situation and having a further setback that will go deeper in the season."

Appel, the club's No. 2 prospect and No. 17 overall according to MLB.com, was never really considered a candidate to make the big league team to start the season, though he's about as polished as you get, considering he spent four years at Stanford. That being said, he would like to break camp with a team -- likely Class A Lancaster -- instead of having to stay in Kissimmee for extended spring camp.

"I want to be ready for Opening Day, wherever I go," Appel said. "I believe I can be ready physically, and that's what my goal is. It hasn't changed since the beginning of Spring Training. Since I had an appendectomy, I made the goal to be ready for the Opening Day of the season.

"That's what my plan is. If the trainers and other people involved in making that decision say otherwise, there's not much I can do about it. I'm going to make the most of it one way or another, but I believe I can and will be there for Opening Day, wherever I go."

Springer, Astros mum on report he declined extension

VIERA, Fla. -- The Astros weren't commenting Wednesday on a FOX Sports report that said the team last year offered prospect George Springer a seven-year, $23 million contract extension, which he turned down.

Springer, 24, hit a combined .303 with 37 homers, 45 stolen bases and 108 RBIs last year between Double-A Corpus Christi and Triple-A Oklahoma City.

Houston general manager Jeff Luhnow said earlier this year Springer would join the Astros at some point in 2014, but he's struggled at the plate this spring and appears destined to start the year at Triple-A. Luhnow didn't comment on the report.

Springer -- Houston's No. 3 prospect, according to MLB.com -- was asked following Wednesday's 2-0 win over the Nationals about the report.

"I'm not going to talk about that," he said. "I'm here to play baseball."

The article suggests the team aimed to sign Springer to buy out his arbitration years, which could become costly if he's as good as advertised. A signing would also enable the Astros to call up Springer at any time without having to worry about the start of his arbitration clock.

Last year, the Astros signed second baseman Jose Altuve to a four-year, $12.5 million extension, buying out his arbitration years (the deal also came with two club options). Moves like that give the player some early financial stability, while the team gets a budget-friendly contract and a low-risk financial gamble.

Prospects' spring struggles not worrying Porter

VIERA, Fla. -- Astros manager Bo Porter said Wednesday he's not concerned about the Spring Training struggles of top prospects George Springer, Jonathan Singleton and Delino DeShields Jr., who entered play with a combined .162 average.

None of the three were expected to make the club out of spring camp, though Springer, an outfielder, and Singleton, a first baseman, are expected to land in Houston at some point this year. DeShields, ranked as the Astros' No. 7 prospect by MLB.com, could be in Double-A at some point this year.

"I think early on, they were probably pressing, just wanting to make a splash or make an impression," Porter said.

Singleton -- ranked by MLB.com as the Astros' No. 4 prospect -- got off to an extremely slow start before hitting his first spring homer March 13 against the Jays. He began play Wednesday hitting .130 (3-for-23), but had drawn nine walks in 32 plate appearances for a .375 on-base percentage.

"I even said to Singleton after he hit the home run, 'I'm so glad you got it out of the way and now you're going to go 10 for your next 10 because you're not trying to hit the ball to Tampa anymore,'" Porter said. "The quality of all those guys' at-bats have been tremendous from my standpoint."

Porter likes the way DeShields has worked counts despite his .143 batting average entering Wednesday. Springer, who was hitting .167 (5-for-30) with one RBI and four steals, has been working on controlling the strike zone.

"No cause for concern at all," Porter said. "You look all the other aspects. You look at some of the things that don't show up on the stat sheet."

Earlier this spring, Springer -- Houston's No. 3 prospect, according to MLB.com -- mishit a ball that glanced off the glove of Nationals pitcher Gio Gonzalez for a hit. He stole second base, and Porter said Gonzalez was so concerned with Springer on base he wound up giving up a two-run homer to Carlos Corporan.

"Those are impactful plays in my eyes," the manager said.

Player options factor into determining roster

VIERA, Fla. -- One of the things the Astros will consider while making their final rounds of roster cuts in the next two weeks will be options. Players who are out of options must clear waivers, which means they could be exposed to being taken by other clubs.

Right-hander Lucas Harrell, who's battling for a spot in the rotation, designated hitter Chris Carter and left-hander reliever Raul Valdes are all out of options. Valdes is certainly on the bubble when it comes to whether he'll make the rotation, but Carter appears to be a lock.

"Whenever you're making decisions on the ballclub, you want to do what's best for the organization," manager Bo Porter said. "The business side of it, all those things come in as factors when you're putting together a 25-man roster."

The Astros certainly weigh options with some level of impact in roster decisions, but the players who perform the best will make the club. However, if there are two players who are on equal footing as far as the type of spring they had, the team could lean toward keeping the player with options so it won't lose him.

Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.