A's manager Bob Geren said on Friday that Braden will miss his scheduled start on Saturday, due to elbow tightness that kept him from taking the mound in Baltimore on Tuesday.
In his stead, right-hander Clayton Mortensen will be promoted from Triple-A Sacramento to start against the host Indians.
Braden, battling a dose of elbow tendinitis, came out of a 25-plus pitch bullpen session on Thursday feeling well, but Geren said the club wants to give him "as much time as he needs to get himself feeling better." Thus, to make room for Mortensen on the roster, Braden is likely to be placed on the disabled list on Saturday.
Oakland can afford to skip Braden's next turn in the rotation on July 8, when the club has a scheduled off-day. Then, with the All-Star break awaiting just four days later, the southpaw can potentially rest until July 20 and jump into the back end of the rotation.
"We'll look at the rotation," Geren said. "We'll consider who needs the most time out."
Mortensen was one of two Sacramento players -- the other Josh Donaldson -- recently named to the Pacific Coast League All-Star team. The 25-year-old righty, owner of a 10-2 record and 3.58 ERA this season, was held out of his scheduled start for the River Cats on Thursday in the event Braden was unable to go.
In 98 innings pitched for Sacramento this year, Mortensen has compiled 77 strikeouts, good for third in the PCL. Meanwhile, he's walked just 31. He made seven appearances -- six of them starts -- for the A's last year, struggling with a 2-4 record and 7.63 ERA.
However, the improvements he's made since then, as noted by Geren, show in more than just his current numbers.
"We'd like to see a performance similar to what he's been doing," the skipper said. "He's been throwing strikes and throwing his sinker for strikes. That's his key pitch, so that's what you want to see."