FORT MYERS, Fla. — Triston Casas is not in the lineup with the rest of the Red Sox big league regulars, and manager Alex Cora indicated he’ll be out for a couple of days due to illness.

“He’s sick, he has the flu,” Cora said. “So he’s going to be out of the facility for two to three days.”

Cora also indicated that two pitchers will be sidelined due to injury as well, including right-hander Bryan Mata and non-roster righty Alex Hoppe. Mata has a pulled right hamstring and Hoppe has a tight lat, which will keep both pitchers sidelined for the time being.

Mata’s injury is a major setback for the former top pitching prospect, who is out of minor league options and has to make the big league team out of camp. Mata is known for his 100 mph fastball and filthy stuff, but injuries and command problems have plagued his development, necessitating a move from being a starter to a reliever.

Hoppe was always a long shot to make the Opening Day roster, but he’s an intriguing arm as well whose fastball can also top 100 mph.

Cora also offered an encouraging update on the club’s three injured position players, saying catcher Connor Wong (elbow soreness) is making progress and that Vaughn Grissom (tweaked hamstring) and Jarren Duran (toe surgery recovery) are trending the right way as well.

“(Wong’s) doing better, he’ll be throwing to the bases midweek, I want to say when we come back from West Palm, but he’s trending in the right direction,” Cora said. “Vaughn is doing well. Jarren is dying to go out there and play but we have to be smart.”

Who’s up next

Tanner Houck will make his first start of the spring on Monday at home against the Philadelphia Phillies, and he’s expected to be followed out of the bullpen by Lucas Luetge, Andrew Politi and Chase Shugart.

Nick Pivetta will not start in the next couple days as expected but will instead throw a two-inning bullpen on Wednesday. Cora said he’s not injured and is way ahead of all the other pitchers, so instead they expect he’ll throw three innings on Saturday.