The Chargers are 2-1 after Sunday's 20-10 loss to Pittsburgh.

The Bolts are home in Week 4 for a matchup against the Chiefs.

Here are five takeaways from Chargers Head Coach Jim Harbaugh's Monday press conference:

1. An update on Herbert

Harbaugh said Monday that X-rays were negative on Justin Herbert's ankle and that the quarterback could undergo more tests in the coming days.

"I'm sure we'll do an MRI, too, as well," said Harbaugh, who didn't have much additional information other than that.

"We're going to evaluate and get treatment," Harbaugh said. "We'll have much more information for you on Wednesday."

The Chargers quarterback, who initially suffered the injury in Week 2 against Carolina, said Sunday he reaggravated it in Week 3 against the Steelers.

Herbert played 36 snaps in Pittsburgh and was stellar in the first half by completing 12 of 16 passes for 125 yards and a touchdown. He compiled a passer rating of 118.0 in the first half.

Harbaugh said he had no regrets about starting Herbert on Sunday and the process used to determine that.

"No, I think it was good. The doctors evaluate, they clear [a player]," Harbaugh said. "Then with your eye, you can see, 'Is he able to perform? Able to do what he has to do in order to protect himself? Does he feel like he can play?'

"All those factors are the pieces to the puzzle," Harbaugh added.

Harbaugh later expanded on the other side of that decision.

"The other [decision] would be, 'No, you can't play. We're going to take it out of your hands and [not] let a warrior be a warrior.' That doesn't resonate with me," Harbaugh said. "And it's Justin Herbert. That don't make them like him. I thought he did great."

Harbaugh noted that high ankle sprains are "not one size fits all" and that each player reacts different given the degree of the injury.

For quarterbacks, Harbaugh said one must "be able to move and be able to push off when you make a throwing motion. Those are critical factors."

2. Info to come on Slater, Alt, etc.

Herbert was one of a handful of Chargers who left Sunday's game with an injury.

Left tackle Rashawn Slater suffered a pectoral injury while right tackle Joe Alt appeared to hobble off the field after the Chargers final offensive play in the fourth quarter.

Outside linebacker Joey Bosa appear to tweak a hip injury that initially occurred in Carolina.

Harbaugh said the team will know more as the week goes on.

"Evaluations today on everybody, treatment," Harbaugh said. "Will be able to give you much better information when the injury report comes out Wednesday."

Slater played 30 snaps before leaving the game in the third quarter. Trey Pipkins III played 45 snaps and eventually replaced Slater at left tackle. Jamaree Salyer played 17 total snaps, with one coming at left tackle before he eventually settled in at right guard.

Harbaugh said the decision to shuffle the line around was because Salyer had "more time on task at the guard position."

3. Week 3 takeaways

The Chargers couldn't hold a 10-7 halftime lead Sunday in the Steelers home opener.

But Harbaugh came away encouraged after watching back the tape of the Bolts first loss of the season.

"The individual play, it was outstanding in many areas," Harbaugh said before rattling off nearly a half-dozen players who stood out.

"Really go up and down the roster, there was some really good play. Team was playing well then each unit had a stretch where the unit didn't really execute, kind of in a row," Harbaugh continued. "Special teams had that, defense had that, offense had that. That hurt us in a tight game. I thought there was some really good play, I guess to sum it up, some really good play.

"Effort was there, and it wasn't our day. They were the better team yesterday and collectively we all just look at it, where can we get better and avoid the stretch of some critical error where we can make it our day," Harbaugh added. "That's really everybody looking at ourselves, individually, collectively, as a unit, where can we avoid that and where can we get it to turn our way."

Entering Monday Night Football, the Chargers rank 15th in Pro Football Focus' total team grade at 72.1.

The Bolts rank 26th in PFF offensive grade (62.4), fourth in PFF defensive grade (75.4) and 18th in PFF special teams grade (67.1).

4. A look at Heinicke

Herbert was replaced by Taylor Heinicke on Sunday as the backup played the Chargers final 10 offensive snaps.

Heinicke, who was acquired in an August 28 trade, has impressed Harbaugh with his preparation and eagerness since arriving.

"He handled it well," Harbaugh said. "The mindset is that it's much better to be prepared and have your opportunity not come, then it is to be not prepared and have your opportunity come.

"I thought he prepared himself really well for it," Harbaugh added.

Heinicke completed a pair of passes for 24 yards but was sacked three times.

Harbaugh said a few weeks ago that the Bolts would tailor specific gameplans for each quarterback (Herbert, Heinicke and Easton Stick), something that will continue going forward.

"We've been doing that, trying to do it as much as we can to get that, be specific for their skillset," Harbaugh said. "Taylor's been good, I thought he acquitted himself really well in the game, checked the ball down, made the nice throw over the middle, has a good grasp of pretty much [everything].

"It's been steps, like we thought we would be able to do and he's really got a good grasp of things," Harbaugh added.

5. Defense bringing the lumber

The Bolts defense matched their Pittsburgh counterparts nearly every step of the way Sunday.

And if you've noticed a different brand of physicality with that unit, you're not alone.

Whether it's Khalil Mack, Derwin James, Jr. or Denzel Perryman, the Bolts have plenty of players flying around and thumping the opponent.

"They are [hitting hard]. Really good," Harbaugh said. "Kind of a critical error here or there, we're capable of playing that kind of defense that we're showing. Been impressive."

James currently ranks 10th among all safeties who have played at least 125 snaps with a PFF tackling grade of 80.8.

Mack, meanwhile, ranks fifth among edge rushers with an overall PFF grade of 87.4 among players with at least 125 defensive snaps.