The Chargers open mandatory minicamp on Tuesday, marking the start of their offseason program in earnest. Minicamp will run through Thursday, after which the roster will resume OTAs from June 16 to 18.

With many new faces expected to contribute for Los Angeles this season, minicamp presents Jim Harbaugh and his staff their first real opportunity at breaking down the roster.

Here are five players whose storylines during the week will be worth watching.

WR Quentin Johnston

Wide receivers coach Sanjay Lal called Johnston a starter during OTAs last week, despite the additions of rookies Tre Harris and KeAndre Lambert-Smith. Lal also said that both rookies are a bit behind the curve as they get into NFL shape, but his comments about Johnston suggest that the Chargers are still confident in the former first-round pick’s abilities. He’ll have to prove that confidence is well-founded with an opportunity to run with the starters during minicamp.

OT Rashawn Slater

Slater has not been present at OTAs, which are not a mandatory team activity, as he and the Chargers continue to negotiate a contract extension. Missing mandatory minicamp would start a holdout, with Slater leveraging his attendance to get the organization to speed up negotiations even as he picks up fines for not being present. But there’s no guarantee Slater won’t come to minicamp, and whether or not he takes the field with the rest of the roster on Tuesday will be the biggest storyline of the week.

OL Zion Johnson

The Chargers seem to remain committed to trying Johnson at center as he enters a contract year, even with the return of Bradley Bozeman and the signing of Andre James. Johnson has also rotated with Bozeman at guard, and Trey Pipkins will likely be a part of that competition when he’s not filling in for Slater at left tackle. With a split of the starting reps at center, it’ll be interesting to see if Johnson takes a step forward and starts to win the job from Bozeman.

LB Junior Colson

Linebackers coach NaVorro Bowman and veteran Denzel Perryman have already told the media that they expect a breakout season from Colson, who is fully healthy after missing a chunk of his rookie training camp and season with various injuries. Colson may not start the week as a full-time starter – Perryman and Daiyan Henley started last season and will likely be the tandem to start minicamp – but his continued progress with a full offseason under him is something to keep an eye on.

EDGE Tuli Tuipulotu

Tuipulotu is stepping into a full-time starting role for the first time with Joey Bosa now in Buffalo, which means it’s time for the third-year rusher to take another step forward if the Chargers are going to remain effective on defense. Tuipulotu has gotten plenty of spot starts while Bosa and Khalil Mack were out with injuries over the last two seasons. Still, it’ll be interesting to see how he handles the pressure of being atop the depth chart next to Mack from the outset this offseason.