The A’s scratched Sonny Gray from his start Tuesday night because of flulike symptoms, recalling right-hander Chris Bassitt from Triple-A Nashville to take his place against the Colorado Rockies.

Manager Bob Melvin said Gray had been dealing with flu symptoms for a couple of days, but they worsened Monday night and Gray spent the night in the hospital. Gray was still in the hospital Tuesday afternoon and was expected to undergo additional tests.

“He’s feeling better today than he did last night,” Melvin said. “It hit him pretty hard.”

The A’s were able to fly Bassitt in from Nashville, where he last pitched on Friday. That means Bassitt will be pitching on short rest, but he threw just 85 pitches in five innings in his last start. Reports on Bassitt’s recent outings, Melvin said, have been “good.”

“Velocity’s been there,” Melvin said. “When he throws strikes he performs well. … That’s what we asked him to do when he went down, was throw the ball over the plate.”

Melvin said no decisions have been made on when Gray will return to the rotation. Assuming Gray returns to health soon, the A’s could just treat this as a skipped start and slot him back into his regular rotation spot next time it comes up. But, Melvin said, “until we find out exactly what’s wrong with him, it’s tough to forecast.”

To make a roster spot for Bassitt, the A’s optioned Max Muncy to Triple A. Muncy had been playing sparingly with the A’s, and Melvin said he may benefit from regular at-bats in Nashville.

The A’s lineup tonight behind Bassitt:

CF Burns

1B Vogt

2B Zobrist

DH Butler

C Phegley

3B Lawrie

LF Canha

SS Semien

RF Fuld

And the Rockies’ lineup behind left-hander Jorge De La Rosa:

CF Blackmon

SS Tulowitzki

3B Arenado

RF Gonzalez

DH Rosario

1B Paulsen

C McKenry

LF Barnes

2B LeMahieu

▪ The A’s agreed to terms with first-round pick Richie Martin on Tuesday and brought him in for a visit that included taking batting practice and grounders at the Coliseum. More on that can be found here.

▪ Melvin said it’s a regular night off for Josh Reddick. Reddick homered Monday night, but Melvin has him on the bench with a day game Wednesday and the A’s facing a left-hander in De La Rosa. The A’s are 4-13 this season when facing a left-handed starter, the second-worst record in the majors only to the Rockies’ 3-12 mark.