Still smarting from their embarrassing performance in getting steamrolled Sunday by the Vikings, the Chargers' defense took yet another hit on Monday.
Castillo is out at least six of the remaining eight games after undergoing ankle surgery to repair a torn tendon.
"To this point when we've had guys injured we've had guys step in and play well," coach Norv Turner said. "That's something we are counting on."
With Castillo down for the count -- maybe for the rest of the season -- Jacques Cesaire and Ryon Bingham will be asked to fill in.
"There are guys practicing and working hard and playing 10, 12, 15 plays a game, and they're going to have to play more."
Castillo is a presence in the run game, which was illustrated on Sunday with the Vikings pushing the Chargers around after his exit with the injury.
The Vikings pounded the Chargers for 305 rushing yards on 25 attempts after Castillo was sidelined.
--QB Philip Rivers is facing additional criticism after a sub-par game Sunday when the Chargers couldn't handle the Vikings' numerous blitz packages. At one point Rivers threw 11 consecutive incompletions on his way to a 19-of-42 performance for 197 yards with an interception and lost fumble. Rivers looked shaky most the day and never did find his rhythm. Coach Norv Turner, though, said he never considered going to backup Billy Volek.
--RB LaDainian Tomlinson was used in a strange manner Sunday as the Chargers -- for some reason -- kept trying to pound the middle of the line. That didn't make sense with a backup center going against the interior of the Vikings' line which features two Pro Bowlers. Tomlinson rushed for but 40 yards on 16 carries -- he did have a TD. But he didn't have as big an impact on the game as he had hoped.
--TE Antonio Gates was basically silent for the entire game. He had but one catch for 10 yards, which is strange considering the amount of times the Vikings blitzed. Gates would seem to be a good, quick safety valve, but he wasn't active in the passing attack.
--WR Chris Chambers was getting open but two things kept happening: Rivers would misfire in his direction or a penalty would bring back a long gain. Chambers is a vital addition to the offense -- that said, the team is still trying to figure out how to use him as he tries to build a bond with Rivers.
--WR Vincent Jackson had a drop and was underthrown on another effort. But what is becoming known around the team -- and the NFL -- is that Jackson seldom fights for a ball. If it's placed in his mitts, he has a pretty good chance of catching it. But on a day in which Rivers was wild, Jackson didn't help his wobbly quarterback by coming back on the ball. This is starting to become a pattern. He did finish with one catch for 16 yards.
--C Cory Withrow was overpowered by the interior of the Vikings' offensive line as the Chargers couldn't handle the blitz and couldn't open running lanes for Tomlinson. Withrow is in there at least one more week as Pro Bowl C Nick Hardwick recovers from a foot injury.
--WR Craig Davis didn't play with a sprained ankle. The Chargers are starting to get frustrated with his lack of contributions. He should go this week, although he has yet to prove he can play with pain.
--WR Legedu Naanee got his first NFL catch and the rookie looked comfortable out on routes. He finished with two catches for 39 yards. He should see the field more, especially if Davis stays down.
--DT Jamal Williams didn't have an impact in his first game back after two knee surgeries during the bye week. It's essential Williams returns to his Pro Bowl caliber play in a hurry on the run defense is in for some long days.
--CB Antonio Cromartie made history when returning a failed field goal 109 yards for a touchdown, his third touchdown in two weeks. Why this guy isn't returning kicks and/or punts is a mystery. One reason is not to get him hurt, Turner said, but when you have a weapon like this, use it.
--CB Quentin Jammer was chased from the game when he aggravated his strained hamstring. This is starting to become a chronic problem and Turner couldn't hide his concern on Monday. Jammer might try to practice later in the week, but there is a real chance he will be down Sunday.
--OLB Shaun Phillips was held out Sunday as the medical staff wasn't certain his strained groin would hold up. But he is expected to give it a good test Wednesday and if he doesn't suffer a setback, play on Sunday.
--ILB Matt Wilhelm had a game-high 14 tackles but most of them came downfield after Adrian Peterson had left a few Chargers in his wake.
--ILB Stephen Cooper was flattened as well by Peterson as the defenders seemed surprised by the combination of Peterson's speed and power. He had six tackles.
--FS Marlon McCree will not be keeping the Sunday game film for his video scrapbook. He consistently took bad angles in trying to catch Peterson and on the occasions he did reach him, McCree bounced off him like a fly on a windshield. Tough day for McCree.
--CB Cletis Gordon is going to be asked to be more involved Sunday, especially if Quentin Jammer is ailing. Gordon could see action in the nickel and dime packages. He got his feet wet Sunday with one tackle.
--P Mike Scifres continued his run of good play by averaging 45 yards net on eight efforts. He had a long of 65 yards and five of his punts were downed inside the Minnesota 20.
Up A Creek Without a Tackle
SD Super Chargers Top Stories
2016 Fantasy: Md-Year Rest of Season RankingsNeed to revamp your Fantasy Football team? Or perhaps your league redrafts at the mid-way point of the NFL season? Check out our Rest of Season Fantasy Football Rankings!
Scout Fantasy11:22 AM
Daily Dr. Roto: Thursday Night PreviewDr. Roto previews Thursday Night Football's matchup between the San Diego Chargers and Denver Broncos from a Fantasy Football perspective!
3 Keys To Victory: Broncos vs. ChargersThe Broncos are coming off their first loss. On their first divisional road trip of 2016, what must the Broncos do to emerge victorious? Chad Jensen turns to the film room.
Mile High Huddle10/13/2016
MHH Predicts: Broncos vs. ChargersWill the Broncos rebound on a short week or will the losses start to snowball?
Mile High Huddle10/12/2016
Week 6: IDP InsiderFantasy Football Expert Mark Morales-Smith provides a must-start IDP list and a few recommendations per position if you need to hit the waiver wire!