WESTFIELD, Indiana -- We're in Indianapolis -- well, 45 minutes outside of Indianapolis -- for joint practices with the Colts. Day 1 of a two-day run arrived Wednesday, with the Colts and Browns taking two full fields and splitting off for practice after individual warm-up periods.

Before we get into the football side of things, Browns fans deserve a pat on the back and a bark or two. They showed up in droves and were ecstatic to be there from the beginning, and Browns players reciprocated, replying to multiple "dawg check" chants with barks.

"I did not expect anything different from them," head coach Freddie Kitchens said of the fans. "We travel good. They are excited, they are passionate. They are the most passionate fans in the NFL and I expected them to be there."

Senior Writer Andrew Gribble kept his eyes on Baker Mayfield and the Browns offense. I took up a post observing the Browns defense. Here are my observations from the first practice against the AFC wild-card qualifiers from 2018.

1. Slow start, strong finish

The Browns are staying in downtown Indianapolis, and Colts training camp is at the Grand Park Sports Campus in Westfield, Indiana, approximately 45 minutes from downtown. That means the Browns have to get dressed in the locker room at Lucas Oil Stadium, then board buses out of downtown to the sprawling complex in suburban Indianapolis. The trip made things different for players, and it showed when the Browns' defense got off to a bit of a sluggish start.

Conversely, the effects of the Browns' physical camp weren't what you might think they'd be. On a fairly frequent occasion, Browns defenders visibly had to let up at the last second instead of tackling Colts to the ground. It's almost as if their adjustment to the different level of practice made them slow up a bit, which understandably showed in the early portions of practice.

Defensive coordinator Steve Wilks looked to his sideline at one point and shouted at his defenders to "pick up the tempo" near the end of an early 7-on-7 period. Things turned shortly thereafter, when a Browns defender stripped a Colts receiver of the football, and Wilks raced nearly 30 yards downfield, shouting "get on the ball! Get on the ball!" Safety Juston Burris did just that, and from there, the defense intensified.

Cleveland did a solid job in a red zone period, allowing just two touchdowns, and only one through the air on a well-run quick slant inside the 5. Things got a little chippy when a few Browns and Colts got involved in a skirmish, but it didn't take long for the two sides to calm down.

"I told them we are not taking anything either, though," Kitchens said of the after-whistle activities. "So, we will see what caused it and what happened and then evaluate the situation. But we are not going to take anything from anybody either."

2. The front four is for real

Colts All-Pro guard Quenton Nelson sat out of practice Wednesday, so the barometer wasn't quite as accurate as we'd hoped, but the prevailing takeaway remains strong: This defensive front four is going to cause many teams problems.

Sheldon Richardson occupied two blockers and plugged gaps consistently, and Larry Ogunjobi enjoyed frequent penetration, recording at least one would-be sack of Colts quarterback Jacoby Brissett. Much of Indianapolis' run plays were strung out outside of the tackle box because Colts running backs seldom found much room to run between the tackles.

"Definitely," Ogunjobi said when asked if he's started to get a feel for how good the group can be. "Just to how we play off each other, the things that we are doing, rushing, stopping the run, those things. It is cool just being able to kind of feel the guys out and understand alright, this is what (DE) Myles (Garrett) likes to do or (DE) Olivier Vernon, (DE) Sheldon (Richardson) and then just work off each other from there."

Again, no Nelson meant a diminished test for the Browns' front four, but Indianapolis still has four other quality linemen in the starting group, and the Browns more than held their own. If a top five line from last season doesn't defeat this group, there might be some ugly days ahead for opponents of the Browns.

3. Close calls in the secondary

The group portion of the afternoon began with one-on-ones -- a drill essentially slightly skewed in favor of the offense -- and the Browns didn't have the best showing.

Indianapolis' two talented tight ends, Eric Ebron and Jack Doyle, feasted in the period. Close calls became receptions for Colts tight ends, with Morgan Burnett making a nice play but still seeing Ebron then bobble and catch the pass, eliciting cheers from the crowd. Simply, one-on-ones weren't the best for the Browns, who were also without Denzel Ward.

That changed in the latter periods, in part because of Wilks' aforementioned request for his players to pick up their pace. Joe Schobert dropped an interception, which landed in the hands of Doyle, to Schobert's dismay. He bounced back, though, breaking up a pass over the middle on the very next play.

His teammates followed suit, breaking up attempts consistently and covering so closely, Colts quarterbacks were frequently forced to check down to running backs in the flats. Rarely did any of Indianapolis' signal-callers air it out, and it only worked once on a touchdown pass to Daurice Fountain.

All of this happened, again, with Ward and T.J. Carrie out. Greedy Williams was solid in his first session against the Colts.

We hear a lot about the Browns' offense, which was good on Wednesday. But this defense has potential to be something special, too, and it showed in the first joint practice.