PITTSBURGH -- The Astros, who promised to be active in the international signing period, announced on Tuesday that they had come to terms on contracts with 16-year-old outfielder Luis Payano, 16-year-old shortstop Kristian Trompiz and 17-year-old catcher Victor Tavarez. Terms were not disclosed.

"The Astros have actively scouted this year's international prospect class," general manager Jeff Luhnow said. "These players are a good start and a continuation of our attempts to aggregate the best young talent in baseball."

Payano (6-foot-1, 175 pounds), who is from the Dominican Republic, was signed by Astros Dominican scouting supervisor Rafael Belen and Felix Francisco, who is Houston's special assistant to the general manager/Latin American operations. "Payano is a high-energy player and can be a five-tool player in center field," Francisco said. "He has the ingredients to become a complete player."

Tavarez (6-foot-1, 193 pounds), also Dominican, was signed by Francisco, Belen and Dominican scout Jose Ortiz. "We have scouted Tavarez for some time and feel he has developed quickly in recent months," Francisco said. "He's a good receiver who can throw well and his bat continues to impress our scouts."

Trompiz (6-foot-1, 170 pounds), who is from Venezuela, was signed by Francisco along with Venezuelan scouting supervisor Oscar Alvarado and Venezuelan scout Daniel Acuna. "Trompiz is a plus defender who can play shortstop," Francisco said. "He has good instincts to play the game and is advanced for his age. He also has the ability to make consistent contact and will improve as he gets stronger."

All three players will report to the Astros Academy in the Dominican Republic.

Johnson unlikely to return before Thursday

PITTSBURGH -- Astros third baseman Chris Johnson likely won't return to the lineup until Thursday at the earliest. Johnson, who was scratched from the lineup Sunday in Chicago with a muscle strain in his left side, is progressing but probably won't quite be ready for Wednesday's afternoon start time.

"I woke up this morning feeling better," Johnson said Tuesday. "I got some treatment, hit off the tee, did some flips [hitting the ball while it's flipped]. We're going to see what the weather does and see if I can get outside and hit batting practice."

The rain held off in Pittsburgh for Johnson to take BP on the field on Tuesday. He said he can't worry about aggravating the injury, which he suffered swinging the bat on Sunday.

"It it happens again, it happens," he said. "I'm just going to go about my swing. I'm just going to go about my normal way, because it doesn't make sense to be passive. That's just not my swing."

Astros manager Brad Mills didn't sound like he wanted Johnson to play Wednesday.

"That might be rushing him back, but we'll see how he feels," he said.

Maxwell opts against surgery, back with Astros

PITTSBURGH -- Outfielder Justin Maxwell rejoined the team on Tuesday after deciding not to have surgery to remove the loose bodies in his left ankle. He was originally set to have surgery, but orthopedist Dr. Kevin Varner in Houston said the issue could be resolved non-surgically.

"He felt confident I would be able not to have surgery," said Maxwell, who's eligible to come off the disabled list after the All-Star break. "So I think this week I will just rest and maybe some time when we go back home I'll go on rehab."

The Astros are hoping Maxwell, who has eight home runs in 121 at-bats this year, can rehab at Double-A Corpus Christi during the All-Star break. Maxwell tested the ankle over the weekend by running, hitting and sprinting, and he had no problems.

"I feel 100 percent," he said. "[Varner] said hopefully it won't bother me the rest of the season and I can revisit it at the end of the year and get it scoped and taken care of and you won't have issues again."

Worth noting

• Astros relief pitcher Wilton Lopez, who's been on the disabled list since June 11 with a sprained right elbow, will fly to New Orleans following Wednesday's game to begin a rehab stint with Triple-A Oklahoma City.

• Matt Sinatro, the Astros' Major League catching and advance scouting coordinator, served as first-base coach on Tuesday and will do so again Wednesday. First-base coach Bobby Meacham returned home for personal reasons. The Astros had to get permission from the umpires to put a uniform on Sinatro, who typically stays in the clubhouse during games.