OAKLAND -- A's right-hander Paul Blackburn won't be a rotation option anytime soon.
One of the club's better performers when healthy last year, Blackburn is still experiencing forearm tightness and has yet to resume throwing.
"He's just not coming along great right now," A's manager Bob Melvin said Tuesday. "He's still feeling some tightness in the forearm."
The A's hoped Blackburn would be able to resume a throwing program 10 days after being shut down, but he's now closer to the two-week mark with no progress to show for the extended rest.
Blackburn was 3-1 with a 3.22 ERA in 10 starts as a rookie in 2017, but his season prematurely ended in August after he sustained a deep bone bruise in his pitching hand when struck by a liner in Baltimore.

"You have to wait until he feels good," Melvin said, "but I know he's a little bit frustrated with the way he feels right now."
Melvin said Blackburn underwent a second MRI this week, revealing the same results. There's no structural damage in the pitcher's arm, a relief considering his symptoms -- forearm tightness is often a precursor to Tommy John surgery.
The A's have already lost Jharel Cotton for the season to Tommy John surgery, and their top prospect, hard-throwing lefty A.J. Puk, is expected to undergo the procedure too. The A's pitching depth has subsequently thinned in recent weeks, which led to the signing of a few familiar faces: Trevor Cahill was inked to a one-year deal, while Brett Anderson got a Minor League contract.
Cahill is scheduled to make his first start for Triple-A Nashville on Saturday, with Anderson penciled in for Monday. Cahill is expected to be in consideration for a rotation spot in Oakland by the middle of the month.
Right-handers James Naile and Frankie Montas and left-hander Eric Jokisch will fill out Nashville's rotation.