ST. JOSEPH, Mo. — Kansas City Chiefs quarterback Patrick Mahomes participated in two rookie-centered, closed-to-the-public training camp practices over the weekend before getting a scheduled day off Monday.Here are three quick observations from watching Mahomes, who has been fully cleared to participate in drills after having surgery to repair the ACL and LCL in his left knee last December.Mahomes is testing himselfThe Chiefs didn’t appear to waste any time pushing the 30-year-old quarterback.During Sunday’s practice, Mahomes was part of a group that worked on rollouts to his left. That throwing movement — while done under the close watch of coach Andy Reid — certainly was designed to put at least some early stress on Mahomes’ surgically repaired left knee.What we learned from seeing Patrick Mahomes on the field againJesse NewellYes, Mahomes still appeared to be favoring that leg a bit. With it being just seven months since he underwent surgery in Dallas, that should be expected.The action, nonetheless, told us something about how Mahomes and the Chiefs are approaching his recovery. They will be monitoring him closely, but they also seem eager to test his limits.The brace will be an adjustmentMahomes said Friday that he felt comfortable playing with a knee brace after using one during part of his college career at Texas Tech.This much became clear in two practices, though: He still will need time to get used to this particular support around his left knee.While recording videos of Mahomes, I was struck by how many times he reached over to adjust the bulky brace. Sometimes, it would be a quick adjustment. Other times, he’d mess with multiple straps, pulling and tugging until he got them into a better position.In other words, Mahomes will be dealing with more than physical limitations when he first takes the field this year. He’ll also have to work around a leg harness that isn’t quite comfortable — at least not yet.Mahomes is practicing a particular setup more oftenThis is my fifth training camp covering the Chiefs, and one thing that has stood out so far is that Mahomes appears to be getting a lot more under-center reps.The Chiefs have typically been a shotgun-heavy team, but that ratio could shift this summer following not only the addition of running back Kenneth Walker III but also after general manager Brett Veach hinted that the team would look to rely more on a downhill run game.In any case, Mahomes has taken pre-stretch snaps under center and also had seven-on-seven passes begin with that same setup.While it remains very early — the Chiefs’ first full-squad practice is set for Wednesday — it’ll be worth watching to see if this trend continues throughout the rest of camp.