Although Pau Gasol is showing "improvement" from a concussion he suffered this week, the Lakers haven't cleared him for basketball-related activities. The Lakers forward saw neurologist Dr. Vern Williams on Thursday on the team's day off, and will do so again this morning in hopes he can play tonight when the Lakers (15-20) host the Oklahoma City Thunder (27-8) at Staples Center. "I keep recovering but I haven't been cleared yet," Gasol tweeted Thursday afternoon. "Rest and patience are important right now." Under the NBA's concussion policy started last season, each player has to pass a series of tests symptom-free before returning to the court. Those steps, according to an NBA official, include the following exercises: stationary bike, light jogging, running, jumping and agility drills and team drills with limited contact. Should a player complete those tests while remaining symptom-free, he'll then be cleared to play without restrictions. The Lakers lost at Houston (Tuesday) and San Antonio (Wednesday) during Gasol's absence, coinciding with other injuries to Dwight Howard (right shoulder) and Jordan Hill (left hip). Gasol suffered the injury in the Lakers' loss Sunday to the Denver Nuggets when Denver center JaVale McGee accidentally elbowed him in the nose. Kobe Bryant suffered a concussion last season in the 2012 NBA All-Star game after Dwyane Wade accidentally elbowed him in the nose. Bryant managed to pass the tests three days after the concussion and didn't miss any games.