Sprits were high throughout the day Friday. The atmosphere was relaxed and on more than one occasion a few veterans cracked smiles as they exchanged jokes. The practices were all-around solid, but lacked the intensity of recent days.  

The highlight of the day came in the morning walk-through when QB Philip Rivers looked like a complete goofball as he ran a deep post pattern as a receiver on a wildcat play. “You run deep and they don’t throw it to you, it is not very fun,” Rivers joked. “I don’t envy those guys. It makes you a little worrisome when they run those deep routes and you don’t throw it to them.”

Possible replacement refs worked the practices and the topic of them potentially officiating regular-season games was a hot topic. “I think the league has a great plan to get these guys ready,” coach Norv Turner said. “It has been great having them out here and we have been doing everything we can to help them.”

OLB Shaun Phillips appeared more honest with his assessment of replacement refs. “Of course [I’m concerned] because the refs we have now miss calls,” Phillips said. “We get some guys out there who are new, of course they are going to miss some calls. But at the end of the day the game should not come down to a referee.”

What stood out: TE Antonio Gates, C Nick Hardwick and ILB Takeo Spikes returned to full participation after Turner had them observe yesterday so others could get more reps. QB Jarrett Lee (undrafted, LSU) has made the most of his extra reps with QB Charlie Whitehurst out (sore MCL). QB Kevin O’Connell, who was signed Monday, managed to get through practice without fumbling a snap but looks lost. WR Robert Meachem had another solid performance with multiple deep receptions. The wildcat was run in both practices. With the signing of RB Ronnie Brown there has been some talk of using the wildcat more, but Philip Rivers said it will never be a staple of the offense. OLB Melvin Ingram (round one, 18th overall) was used in a variety of formations, including as a DE in a 4-3 nickel package.

“Offensively we give [Ingram] a lot of different looks,” Turner said. “We try to get them confused. I think he has done a good job of handling that. He plays both sides, so certainly his versatility with help us.”

Position battles: SS Atari Bigby returned to full participation and played with the first team. SS Brandon Taylor (round three, 73rd pick) saw the majority of the first-team reps when Bigby was out. TE Dante Rosario (free agent, Denver) continues to touch the ball often and appears to have the inside track to a roster spot over returning veteran Kory Sperry. RB Michael Hayes (Houston), OT Mike Harris (UCLA) and CB Greg Gatson (Arkansas) are three undrafted free agents who continue to see significant playing time because of injuries to projected starters.

Injury updates: Starting LT Jared Gaither observed practice. This is progress because Gaither has been missing for full practices since he left the first full practice of camp with cramps. G-T Brandyn Dombrowski (foot, cyst) has yet to participate and had not passed his physical but is out of a boot. G Johnny Troutman (round seven, 250th overall pick) continues to rehab a torn pectoral muscle, but likely will not play this season. QB Charlie Whitehurst, CB Antoine Cason, CB Marcus Gilchrist, OLB Larry English, T Phil Trautwein and WR Eddie Royal all worked on the rehab field, most are expected to return in a few days. WR Richard Goodman observed. DE Corey Liuget returned to full practice.

What's next: The Chargers will host FanFest at Qualcomm Stadium on Saturday. Parking and admission are free. The stadium parking lot will open at 8:00 a.m. and the gates will open at 9:30 a.m. A full team practice will take place from 10:15 to noon.

Follow Chargers reporter Dan McLellan on Twitter @CBSSportsNFLSD and@SanDiegoSports.