Three months ago, the man on the cart was Mathews.
On Sept. 19, it was Tolbert who helplessly watched his teammate be shuttled away. It was Tolbert who was asked to fill Mathews' void. And it was Tolbert who did.
Mathews said Sunday's season-finale game against the Denver Broncos is his chance to return the favor.
"Mike balled out when his number was called," said Mathews, who suffered a high right ankle sprain against the Jaguars in the second game of the season and has missed four full games this season. "He did everything he needed to do to make this team successful. Now it's my turn. I've got to do the same thing. Hopefully I have as much success as he did."
Tolbert was placed on injured reserve Friday for the injury he sustained in the first quarter of the Chargers' 34-20 loss to the Bengals. The undrafted third-year veteran set new career highs in 2010 with 182 carries, 735 yards and 11 touchdowns.
In the Chrargers' first matchup with the Broncos, Tolbert rushed 25 times for a career-high 111 yards and a touchdown. It was one of three 100-yard games by Tolbert, including two with Mathews inactive.
After Tolbert left last week's game, Mathews had 12 carries for 55 yards. He broke off a 23-yard touchdown run in the third quarter, his longest of the season.
Mathews is expected to see a featured role Sunday alongside Darren Sproles against the Broncos' 31st-ranked rush defense. Curtis Brinkley was signed from the practice squad Friday for added depth.
"I wish Michael could play in this game, but it does change the role for Ryan," coach Norv Turner said. "Ryan's going to get a chance to play a complete game. Ryan had to come out of the game the other day when he got his ankle twisted, and he was out four or five plays, so he's not at 100 percent. We'll give [the Broncos] a dose of Ryan and then mix it up with Sprolesy."