We’ve reach the final week of Chargers Organized Team Activity (OTA) practices as the Bolts practiced Monday for just under an hour in helmets and shorts.

Jim Harbaugh’s team will also hold three more OTAs this week before a three-day mandatory minicamp from June 16-18 at The Bolt.

Here are three observations from the Chargers OTA practice on Monday:

1. Plenty of O-line combinations

Chargers offensive line coach Butch Barry took to the podium Monday morning and spoke with reporters for nearly 20 minutes in an in-depth look at the offensive line.

Barry was the Dolphins offensive line coach for the past three seasons under Mike McDaniel and also previously worked with the Chargers Offensive Coordinator in San Francisco.

“Energy is really high and it’s a lot of fun,” Barry said about the vibe in OTAs. “And that’s how I like to conduct myself so I really enjoy it a lot.”

There’s also plenty of competition, too, as the Chargers continued to mix and match offensive line combinations in Monday’s brief practice.

As we enter mid-June, there appear to be four players who are in line to start: left tackle Rashawn Slater, center Tyler Biadasz, right guard Cole Strange and right tackle Joe Alt.

Slater hasn’t taken every rep at left tackle as he works his way back from a torn patellar tendon, but the other three players have been locked into their respective spots.

The main competition has been at left guard, where Kayode Awosika and rookie second-round pick Jake Slaughter continue to rotate up front. Awosika has been up first in drills before Slaughter comes in to split reps.

Barry spoke Monday about both players.

“It’s great, he’s learning everything. He’s doing center, he’s doing guard, he’s doing a lot of different things,” Barry said of Slaughter, who also took some reps at center on Monday. “He’s been great to work with, he’s really, really sharp, he’s all in on it, he loves ball.

“Everything from the draft process, he’s really tough, a lot of great things and qualities about him that he loves. He’s doing a great job,” Barry added.

Barry later added about Awosika:

“Kayode has done a nice job. He’s a guy who’s been around football for a while, veteran player, has done really good things. He’s all in, he’s been great with the group,” Barry said.

The next group was made up, from left to right, Trey Pipkins III, Ben Cleveland, Jacob Spomer, Trevor Penning and Branson Taylor.

The final combination included, from left to right, Travis Burke, Logan Taylor, Spomer, Taylor and Laekin Vakalahi.

“Everyone is competing,” Barry said. “It’s awesome, we’re rolling different guys. Like Coach [Harbaugh] says, all competitors are welcome.”