"To some extent, they're under more scrutiny," Astros general manager Ed Wade said. "There is a timetable that dictates you have to make your determination sooner rather than later. Every time one of those guys steps on the mound, you're going to have to be bearing down on what they're seeing."
Rodriguez was taken from the Tampa Bay Rays in the first round of the Rule 5 Draft and Pendleton, a Houston native, was taken in the second round from the Yankees. They are both competing for the fifth spot in the Astros' rotation.
Not knowing if they're going to be sent back to their former teams comes with a measure of anxiety.
"I try not to think about it," Pendleton said. "I think I'm here for a reason and that I have a chance to make the team and I'm planning on doing that. If it happens, it happens and you've just got to keep getting better no matter which way you go. You have to continue to take baby steps and improve your game."
Rodriguez said he doesn't feel any extra pressure.
"I'm going to do whatever I did before, pitch and work hard, and if it happens that they send me back I'm going to work hard there, too, to make it to the big leagues," he said. "I have a good chance to make it here, too. I'm going to work hard to pitch Houston in the big leagues."
Astros relief pitcher Wesley Wright understands what Rodriguez and Pendleton are going through. He came to camp in 2008 as a Rule 5 pick from the Dodgers and wound up winning a spot on the team. He pitched in 71 games in relief for the Astros that year, but has split the last two years between Triple-A and Houston.
"For the most part, people had never heard of me, so I kind of flew under the radar," Wright said. "It was my first big league camp and there was a lot of excitement in that aspect of it. I knew I didn't have much to lose besides the opportunity to be on a big league roster.
"I just tried to have fun with it. I knew nothing was really promised, so it was a chance for me to learn and I parlayed that into getting a spot. I was a good experience overall and now being my fourth camp with the Astros, it's a little bit different."
Rodriguez, 23, went 7-5 with a 3.80 ERA in 27 games (17 starts) in the Rays' Minor League system last year, splitting time between Class A Montgomery and Double-A Durham. He features four pitches with a loose arm and a projected 6-4, 200-pound frame.
"The scouts that had the coverage for him really liked his arm and felt he could really compete for a spot on the club," Astros director of baseball research/pro scouting coordinator Charlie Norton said. "Make-up wise, everything came back good. He's a good kid and works hard and we just overall felt if given the opportunity, he would at least compete."
Pendleton, 27, has pitched in the Yankees system since being selected in the fourth round of the 2005 Draft. He was 12-5 with a 3.61 ERA in 29 games last year (27 starts) between Double-A Trenton and Triple-A Scranton/Wilkes-Barre with 57 walks and 133 strikeouts.
"I don't know about being under the microscope, but I'm sure I am," he said. "I don't feel that way. Everybody I've come in contact with is real nice and made me feel real comfortable, not like I have pressure on me to show what I've got or I'm out. But the truth is that's the truth. You've got a one shot deal and you have to do something to prove yourself. I'm just happy for the opportunity."
The chance to be with the Astros on Opening Day is even more special for Pendleton, who grew up in the Houston suburb of Kingwood and attended Rice University. He was an Astros fan as a kid and said playing for the hometown club would be gratifying.
"It would be a dream come true just to be on a big-league team, but even more with the hometown Astros," he said. "I can tell you mom is real excited."