Los Angeles Chargers wide receiver Keenan Allen was not at practice for a second straight day on Thursday.
Allen was listed with a knee injury, although Chargers head coach Anthony Lynn said earlier in the week that he thought the team's No. 1 wide receiver was fine.
The sixth-year wideout is tied for the team lead in receptions with 17 for 219 yards and a touchdown. Los Angeles hosts the San Francisco 49ers on Sunday in a matchup of 1-2 teams.
Allen played in 16 games last season, making 15 starts, and set career highs with 102 receptions for 1,393 yards. He also had six touchdowns in earning his first Pro Bowl berth.
A third-round draft pick of the Chargers in 2013, Allen notched at least 67 receptions in each of his first three seasons and scored a career-high eight touchdowns in his rookie campaign.
Allen has dealt with a pair of major injuries that derailed half of one season and almost all of another.
In 2015, Allen had 67 receptions in eight games before his season ended due to a kidney injury.
Allen then suffered a torn ACL in the 2016 season opener, but he came back to play in all 16 games for the first time in his career in 2017.