Pressly is day-to-day, which Baker learned Monday.
The manager also mentioned Devenski dealing with soreness.
The Astros are stocking their bullpen with young players -- five rookies have appeared in the team's first four games this season.
"Thank God that we have some of these young guys to bail us out," Baker said. "I've been talking to the young guys like, hey man, we're depending on you. Just go out there and be yourselves."
Baker said he believes the quick ramp-up to the season is responsible for a lot of the arm soreness around Major League Baseball.
Astros ace Justin Verlander was put on the 10-day disabled list with a forearm strain.
Clayton Kershaw was scratched from the Dodgers' Opening Day start last week because of back stiffness, but he's expected to throw a bullpen session at Minute Maid Park on Tuesday when they visit the Astros.
"I think it has a lot to do with it," Baker said. "A lot of the hitters are ready probably in about three weeks or so, a lot of the guys. But the pitchers need that extra time. They need that five weeks of spring training, or six weeks of spring training. This has been abbreviated and you see it. It's all around baseball. It's everywhere.
"So, I'm just hoping that we learn a lesson by this. It couldn't be helped because of the coronavirus, but I'm just hoping that we don't see anymore injuries around the league, especially on our team."
The Astros won three out of four games at home against the Seattle Mariners to start the season. They open a two-game home series against the Dodgers on Tuesday.