HOUSTON — MetsIt’s starter Paul Blackburn felt a little sore the morning after pitching in a minor league game in the backfields at Clover Park on Saturday, March 22.

“Nothing crazy,” Blackburn told reporters.

The next day, Monday, March 24, his knee developed a “sack of fluid” that made it hard for him to see his kneecap.

“We just essentially had to drain and then inject some gel (into) it,” Blackburn said. “So you have to wait seven days to kind of let that gel do its thing and then go from there.”

By Friday, when Blackburn spoke to reporters, the fluid drain and injection seemed to have done the job. The veteran right-hander reported that he “felt great” and was able to rotate it again.

He does not expect any setbacks and should be ready to resume throwing on Monday.

“(It’s) pretty scary, and then he worked so hard in the off-season,” Mets manager Carlos Mendoza said. “He’s having a really good camp, feeling good and then for this to pop up in his last start during spring training. But he’ll get through it.”

This isn’t the only injury Blackburn has dealt with since arriving to the Mets via trade ahead of last season’s trade deadline.

Blackburn landed on the IL after taking a line drive on the hand against the Padres on Aug. 23. The Mets were hoping he’d avoid an IL stint after a CT scan revealed a bruise, but after the veteran starter felt “a lot of stiffness and soreness,” he was moved to the 15-day IL.

After returning, he began dealing with a spinal fluid leak that required cerebrospinal fluid leak repair in the offseason.

“It’s frustrating, definitely. But I think with this, it could have been structural damage, could have been a lot of other stuff. Instead we’re just like, ‘Hey, we just have to drain this and kind of wait a week, and then we’re able to just kind of pick up where we left off.‘”