Hernandez has been sidelined since April 25 with bursitis in his right shoulder, and any slowdown in his return means he's certainly not going to be back before June, given he'll need to build his arm back up and likely pitch at least one Minor League rehab game before being ready to rejoin Seattle's short-handed rotation.
Things are progressing better with two other key Mariners on the disabled list. Left-hander James Paxton played catch at 60 feet for six minutes on Thursday and will continue ramping up his throwing program now.
Since Paxton has only been sidelined since May 2 with a strained left forearm, he won't need as long to build back up. He could potentially only need a simulated game instead of a Minor League rehab start, so it's possible he could rejoin the team at some point during the next road trip from May 23-30 through Washington, Boston and Colorado.
Rookie outfielder Mitch Haniger, who was hitting .342 in 21 games when he strained the oblique in his right side on April 25, could also potentially be ready at some point later this month.
"Haniger has been swinging in the pool, and tomorrow [he] is supposed to go out and hit off the tee and start working there," Servais said. "He's moving along very well."
• Servais had no word yet on Hisashi Iwakuma, who was scheduled to have doctors test his sore right shoulder after going on the 10-day disabled list Thursday and flying back to Seattle. He is the fourth Mariners starter to go on the DL. Drew Smyly, who was the first to go down and is on the 60-day DL with a strained left elbow, is slated to begin throwing later this month.
• Reliever Steve Cishek threw a scoreless inning of relief for Triple-A Tacoma on Thursday, with one walk and two strikeouts. He will make one more rehab outing with the Rainiers this weekend, then could be ready to join the Mariners when they return home Monday. Cishek underwent left hip surgery in October and has now pitched in six Minor League rehab games with Tacoma and Double-A Arkansas.
• Catcher Mike Zunino homered in his second straight game for Tacoma on Thursday, and he is 3-for-7 with three runs, two RBIs and a walk in his first two outings since getting sent down.
• Center fielder Leonys Martin is also heating up in Tacoma, where he's hit safely in 10 of 11 games and is batting .254 with five doubles, a triple and a home run in 59 at-bats going into Friday's action.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB. This story was not subject to the approval of Major League Baseball or its clubs.