Still, Castillo has been merely average since signing a rich contract a few years ago and Cesaire was seen more of a complementary piece than a starter until thrust into that role last year.
So when Chargers general manager A.J. Smith has the draft eyes turn to him, he could turn to a fresh defensive end.
Of Castillo and Cesaire, Castillo is more likely to remain as a starter. Cesaire could return to his backup role if Smith reaches for the right player with his first pick at No. 18 overall.
Among the defensive ends catching the Chargers' eye is Iowa's Adrian Clayborn. The 6-4, 285 pounder is coming off a decent Pro Day last week, although the Chargers weren't among the teams getting a first-hand look.
Clayborn's game is his speed and quick step off the snap. He could cause havoc with his burst, but some wonder if a lack of impressive strength would diminish his grade.
He did but 17 reps at 225 pounds at his Pro Day, but showed enough skills in other areas to keep on the radar.
Another end is California's Cameron Jordan. Jordan goes 6-4, 282 and played up and down the line last season for the Bears, a year in which Jordan's effectiveness became more apparent.
He's a thick, well-built player with a solid anchor making him tough to get off his feet. And with his length and agility, it can be troublesome to try and re-route him away from the ball. Jordan isn't a flash when getting off the ball but does well enough to get the job done.
Purdue's Ryan Kerrigan is the type of player Smith always tries to gravitate to - someone with skill, an impressive work ethic and a high-character guy.
Kerrigan, 6-4, 263, doesn't take plays off and seems to create a step to exploit blockers by the use of his hands and his upper-body strength. He is not a speed-burner off the line, instead gaining space and leverage by clubbing his way into the backfield.
It seems Kerrigan's stock is rising the more people get a look at him. The Chargers are intrigued and could snatch him off the board - if he's still there.
DE J.J. Watt
With his length, frame and top-shelf first step, he can easily get into blockers before they are set to absorb his energy. And it's believed he will add even more girth to his build as he matures as it looks like his body can handle it.
He's also good at the point of attack and should hold up well against the run.
Watt has plenty of upside and would fit nicely opposite Castillo in the starting lineup.
Smith might have to work his magic in trading up to snag North Carolina's Robert Quinn. Smith might also have to bury the character card, as Quinn was involved in an agent scandal and didn't play in 2010 after an impressive 2009 season when some said he was among the best pass rushers in college football.
He's good in using his hand in that he can usually shed the first block and get up field quickly. He's long and lengthy and blockers sometimes find it difficult to get into him very long or at the right position of his body.
Quinn needs work against the run and also getting off the ball in a timely manner.
--DE Luis Castillo, like other Chargers, is hopeful regarding the lockout. "The tough thing for players is, for the most part, we're on the outside looking in," Castillo said. "We're putting our faith in a group of guys to lead us in a certain direction, and I think for the most part we think they're doing a good job."
--Led by QB Philip Rivers, about 10 players began working out March 21.
Rivers said, "We have to prepare as if there is going to be football. "But it's more about being around each other right now."
He added, "I think it will grow. I've talked to a lot more guys than that ... I just wanted to touch base with everyone and make sure the mindset is we want to get better. We want to be better than last year, we want to win a championship."
QUOTE TO NOTE: "Mark my words, there will be football played in 2011." -- ILB Kevin Burnett on what he thinks will happen with the labor dispute.
OTHER TEAM NEEDS
Inside linebacker: With starters Stephen Cooper and Kevin Burnett both expected to be declared free agents when the labor dispute is over, the Chargers are thin at this spot. It's believed the Chargers will keep just one, and it will likely be Burnett as the wear and tear is starting to catch up with Cooper.
Right tackle: The Chargers have long talked about upgrading the spot held down by Jeromey Clary and this could be the year they do it. The depth behind him, with Brandyn Dombrowski now playing left tackle, isn't stacked.
Wide receiver: Vincent Jackson will likely return as the franchise player and the Chargers are hopeful Patrick Crayton rebounds after the last half of his season was derailed by a wrist injury. But behind those two - save Malcom Floyd - there's not much.
--WR Vincent Jackson.
--LB James Holt: Potential ERFA; terms unknown.
--DT Ogemdi Nwagbuo: Potential ERFA; terms unknown.
--S Bob Sanders: FA Colts; 1 yr, terms unknown.