SAN DIEGO -- The ceiling for Padres outfielder Jabari Blash and right-hander Luis Perdomo is extremely high. There aren't many people in the organization who doubt that.
But, as Rule 5 players on a Major League roster, the Padres have to be just as concerned about their floor. That's because, if the club hopes to keep Blash and Perdomo past this year, the pair must remain at the big league level for the entire season.
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"We don't want to hamstring our team and hamstring [manager] Andy [Green], and we want to put our best 25 on the field," said Padres general manager A.J. Preller. "But going into this thing, we feel like those guys have a chance to help us both short-term and long-term."
By definition, Rule 5 players must remain on the big league roster for the duration of the season or be offered back to their former club after clearing waivers. The rule is in place to give players a Major League shot that they would not have received elsewhere.
Blash, who spent six seasons in the Mariners' organization, would have been in contention for a roster spot, even without his Rule 5 status. His immense power could make him a solid threat as a pinch-hitter late in games.

Perdomo, on the other hand, has never pitched above Class A -- and he struggled mightily in Spring Training, finishing with a 14.63 ERA. At just 22 years old, there's little chance he'd make the big league club, if not for the fact that the Padres would like to keep him past 2016. They view Perdomo as a potential starter in future rotations.
But Perdomo saw a marked improvement toward the end of camp -- an improvement that came around the same time he began developing a split-finger fastball. He allowed just two runs on three hits over his final three outings (4 IP).
"It slowed down the last few times out, and we saw what he is and what he can be," Green said. "We're buying what he is and what he can be."
The Padres entered camp with four Rule 5 selections on their roster. Left-hander Blake Smith was ultimately returned to the White Sox, and righty Josh Martin was designated for assignment Sunday. The club has 10 days to find a route to keep Martin.
If Preller manages to retain him, it could be via trade, rather than by reinstating him to the big league club. Having two Rule 5 players on a roster would figure to complicate things enough.
If Blash or Perdomo -- or both -- struggle, there's no option to hide them in the Minor Leagues. If the Padres have one or two players day-to-day with minor injuries, that could thrust the pair prematurely into the spotlight.
Green thinks they're ready.
"It's not just, 'Hey we're going to carry you for 162 games just to have you for next year,'" Green said. "They're expected to produce, and we keep them because we think they can produce.
"We think they bring something to the table in each case. Perdomo -- that's a nice arm to have in long relief, and Jabari's got the power that we all know about and the walks. They've got to produce, or else you get in the middle of the season and you've got a roster crunch."