2012-2013
In Kawhi Leonard’s second year, he missed 18 games to start the season then another five games off and on that year with what was described as lingering soreness from the same issue, in the tendons at the quad and knee. The 24 games he’d miss would be later classified as “jumpers knee.”
In case you’re curious, jumper’s knee, according to Sport Specific Biomechanics:
"“is believed to be caused by repetitive stress placed on the patellar or quadriceps tendon during jumping. It’s an overuse injury, and one that is also caused by poor-alignment or motion.“"
Likely the aggressive rehab he was doing in fall of 2017 was geared towards correcting the alignment or movement problems.
Recall:
2013-2014
He declined to participate in USA Basketball competition because of the quad and was able to avoid setback of the injury in his 3rd (Finals MVP) season.
He elected to rest again that following summer instead of USA ball. Harvey Buck of the San Antonio Express-News discussed how resting an overuse injury and a potential looming max contract may have played a roll in that choice.
2015-2016
Thankfully, we wouldn’t hear the “Q word” again until March 2016, when he’d sustain what was called a “quad contusion.” After banging legs with Amar’e Stoudemire, Leonard rubbed his knee and would end up missing three games.
2016-2017
We’d get another one of these quad contusions in 2017, though it would only cost him one game.
2017-2018
We learned he may not be ready for the start of the upcoming pre-season on September 30th, because he was still rehabbing the quadriceps tendinopathy from “last-year.” Team President and Head Coach, Gregg Popovich, said it was totally unrelated to the ankle that cost him games in the 2017 playoffs against Houston and Golden State.