In the past, injuries and ineffectiveness have caused the Padres to shuffle pitchers through the rotation early in the season.
But through the beginning portion of 2014, that hadn't been the case as the Padres were one of only three Major League teams to have all five starting pitchers make every turn in the rotation.
That streak will end for San Diego in Sunday's series finale against the Rockies at Coors Field after the Padres placed scheduled starter Andrew Cashner on the disabled list Saturday with soreness in his right elbow.
The Padres didn't have to look far for a replacement, as right-handed rookie Donn Roach -- one of two middle relievers on the team -- will start his first Major League game.
San Diego manager Bud Black said Roach (1-0, 2.57 ERA in 12 games) could throw upwards of 60 pitches -- possibly more.
"If it's an easy 60, he might keep going," Black said. "But I doubt we'll take him into the 80s."
Roach's longest stint this season was 4 1/3 innings, though he has made 54 Minor League starts before this season, so starting again won't be a big adjustment.
"With Monday's off-day, I think that because he's [Roach] here, we know what we're getting," Black said. "And we have Stauff [Tim Stauffer] and [Alex] Torres who can give us length."
Roach will face Rockies right-hander Juan Nicasio, who has pitched well in his previous four starts, going 2-2 with a 3.22 ERA in 22 1/3 innings.
The 27-year-old from the Dominican Republic missed the second half of 2012 following microfracture surgery on his left knee and wasn't really the same until this year. He has bounced back nicely in eight starts spanning 45 1/3 innings, going 4-2 with a 3.77 ERA despite yielding seven home runs.
Unlike many pitchers, this year he has been better at Coors Field (3-0 with a 3.10 ERA in five starts) than he has been on the road (1-2 with a 4.96 ERA in three starts).
In his last outing, Nicasio dropped a 4-1 decision to the Reds at Great American Ball Park, but actually pitched relatively well over six innings, allowing just four runs, two earned, on five hits while striking out three and walking one.
Padres: Leaning on Street
Good things happen when the Padres get the ball and the lead into the capable hands of closer Huston Street. Finding him work, though, hasn't been easy.
Street, who has converted all 13 of his save opportunities, pitched Saturday for the first time since May 13 against the Reds. When he gets in games, he has been very good, as he hasn't allowed a run in 17 of his 18 appearances.
"When he's going well, it's tremendous command," said Padres manager Bud Black. "The catcher is on the corner and he [Street] hits the mitt with three pitches."
The only earned runs Street has allowed this season came on a home run to Brandon Belt of the Giants on April 18.
Rockies: Rosario likely to return
Rockies manager Walt Weiss indicated on Friday that catcher Wilin Rosario will likely return from the 15-day disabled list on Sunday after a few rehab games with Triple-A Colorado Springs.
Rosario hasn't played in a Major League game since May 2 after contracting a flu virus that landed him and teammate Josh Rutledge on the DL.
Before he got sick, Rosario was hitting .239 with three home runs, 15 RBIs and five doubles in 24 games.
• The Rockies are 14-6 at home this season and host the division-leading Giants for three games after San Diego leaves town beginning Tuesday.
• The Padres are 6-4 in their last 10 games.
Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.