When they play: Week 13 (Dec. 4) in San Diego.2015 record: 4-12.Last time vs. Bucs: The Bucs won 34-24 in Tampa in 2012. Down 21-17 at the half, Leonard Johnson had a key 83-yard interception return for a touchdown as part of the win.2016 outlook: The Chargers won less than seven games for the first time in a decade under Philip Rivers as starting QB. Despite a promising young back in Melvin Gordon, they went three months between games rushing for even 100 yards as a team. With the Broncos and Chiefs still as playoff contenders and the Raiders on the rise, San Diego could struggle enough to cost Mike McCoy his job.Player to watch: Rivers won three playoff games in his first three years as starter, but in seven years since, he has none, despite throwing for 203 touchdowns against only 99 interceptions. He turns 35 in December, so as prolific as he's been, will his legacy be good teams that were never great?Rookie to watch: We could mention top pick Joey Bosa, whose holdout could limit his early production, but instead we'll try second-round TE Hunter Henry. He'll take over for LaDarius Green and learn from the ageless Antonio Gates. Henry could challenge Travis Benjamin to be Rivers' No. 2 target behind Keenan Allen.Key matchup: Melvin Gordon vs. rookie disappointment. Gordon was so prolific in college, yet his 3.5 yards per carry were the worst of 30 NFL backs with 150-plus carries. San Diego ranked 31st in rushing (84.9 yards) and worst in average and rushing touchdowns (4). There's huge room for improvement in Gordon's second season. Familiar face: Riverview grad Jahleel Addae settled in as a starting safety last year and now has 151 tackles in his first three NFL seasons out of Central Michigan. Brother Jahmile is the running backs coach at Cincinnati.Cool stat: Through a combination of injuries and parity, San Diego had no player reach 1,000 receiving yards last season, but had seven top 400 yards -- four receivers, two tight ends and RB Danny Woodhead. Getting a healthy Allen will help this offense get more touchdowns to show for all those yards.