SEATTLE -- An already inexperienced Mariners catching situation got even thinner heading into Friday’s Opening Day in Houston as starter Tom Murphy has a broken bone in his left foot and will be placed on the 10-day injured list, the club announced Wednesday.

Murphy took a foul ball off the foot in an intrasquad game on July 14, and initially, he was believed to have a bruise, but the problem lingered and an MRI test ultimately revealed a fractured metatarsal bone.

Murphy will officially go on the IL on Thursday, when the team finalizes its 30-man roster prior to MLB’s 9 a.m. PT deadline. The injury isn’t expected to keep Murphy out for an extended period, but it will force the team to open the season without its one experienced catcher.

“It is a blow,” manager Scott Servais said. “I feel really bad for Murph. This guy works as hard as anybody we have. He comes to the park with a great attitude every day. But things happen. I’m hoping he’s not down too long, but you also don’t want him to rush back. We want him to be 100 percent when he gets back. It’s baseball, it throws you a bunch of curves. We have to adjust.”

The Mariners traded Omar Narváez to the Brewers last winter to open the door for Murphy to take over as the starting backstop, with Austin Nola inheriting the backup duties. Murphy had a breakout season last year for Seattle, hitting .273 with 18 home runs in 75 games and providing solid defense in 66 starts behind the plate.

But with Murphy out, that leaves Nola -- a versatile 30-year-old who has started just four MLB games at catcher -- as the primary starter. Nola came up in the Minors as a shortstop before converting to catcher in 2017 while with the Marlins. The Mariners are high on his catching abilities, and he hit well in a utility role as a rookie last year.

The likely new backup will be Joe Hudson, a 29-year-old non-roster invitee who also has just four MLB starts in brief big league time with the Angels and Cardinals over the past two years.

Hudson missed time in early Spring Training with a sore oblique and was one of the late arrivals to Summer Camp before being cleared last week, but the Mariners aren’t eager to rush top catching prospect Cal Raleigh or Minor League Rule 5 pickup Brian O'Keefe, neither of whom have played above the Double-A level.

“I think so,” Servais said when asked if Hudson could be ready on such short notice. “Joe really brings a great attitude. He’s done a nice job defensively and is a very outgoing personality, a guy that is in the middle of all our meetings and grasped what we’re trying to get done with our pitching.”

Either Raleigh or O’Keefe will now need to accompany the team on the season-opening trip to Houston and Anaheim as the mandatory third catcher on the three-man taxi squad. That taxi squad is being instituted this season, since replacement players won’t be allowed to be flown in on commercial flights as in the past, should anyone on the 30-man roster become injured or ill.

Adams might not be ready either
Reliever Austin Adams, who figured to be one of Seattle’s late-inning options, is another candidate to open the season on the 10-day injured list, as Servais said the right-hander might have pushed too hard to come back quickly from a torn ACL ligament in his left knee.

Adams had surgery on the knee in October and worked diligently to be ready when the club regrouped for Summer Camp three weeks ago, but he’s been held out of action since his second intrasquad outing on July 14.

With free-agent signee Yoshihisa Hirano already on the injured list while returning from a bout with COVID-19, that would leave Matt Magill and Dan Altavilla as the likely closing candidates to open the season.

Sheffield ultra-sharp in final outing
Rookie southpaw Justus Sheffield breezed through four perfect innings with eight strikeouts while facing a lineup of Mariners backups and prospects in the final intrasquad game of Summer Camp on Wednesday.

Sheffield will face the Angels next Tuesday in his regular-season debut.

“I felt pretty good,” said the 24-year-old. “I knew this was the last one. I tried to turn it up.”

Fellow rookie Justin Dunn didn’t fare as well while facing what figures to be close to Seattle’s Opening Day lineup, as he allowed eight hits and three runs in 2 2/3 innings, including a leadoff homer by Shed Long Jr. and a pair of singles to Kyle Lewis.

Evan White hit a pair of doubles as he and Lewis concluded their strong Summer Camps.