For Blake Costanzo, August is the season for antacid.

Throughout his improbable seven-year NFL career, Costanzo, a try-hard, undrafted special-team standout from Lafayette College, has experienced the late-summer sweats as he fights to win a job.

“Every training camp I’m miserable, man,” Costanzo said. “I’ve got my bags packed the whole time ready to go home.”

This summer, Costanzo has good reason to pop Pepto given his age (30), salary ($855,000) and the competition on the 49ers’ special-teams units.

After spending two years with the Bears, Costanzo returned to the 49ers in June and reunited with teammates he played with in 2011 when he ranked second on the team with 17 special-teams tackles.

He not only returned with his job-security angst, he also brought back his sense of humor.

For example, Costanzo was thrilled to see 49ers linebacker Dan Skuta, a fellow special-teamer he faced for two seasons in the AFC North when Costanzo was with the Browns and Skuta played with the Bengals. Part of Costanzo’s excitement came from finally realizing he was 15 pounds lighter than the 250-pound Skuta.

“I had some battles with Skuta, man,” Costanzo said. “I remember thinking, ‘Geez, this guy is really good.’ But when I got here I was like ‘Well, at least this guy’s bigger than me.’ I thought he was my same size, so it gave me some comfort knowing that he was a little bigger.”

Costanzo can now count Skuta as a teammate – and part of his formidable competition. The 49ers return all eight of the players who had at least seven special-teams tackles last year when they ranked fifth in the NFL in opponent’s kickoff-return average (20.4) and 13th in punt returns (8.7).

Among that group is a player such as cornerback Darryl Morris, who is younger (23) and cheaper ($495,000) than Costanzo, whose $855,000 veteran minimum salary is based on his seven years of service.

“That’s the way the league is going,” Costanzo said. “Teams can get a couple younger guys for the price of an older guy. Once you get up in years your salary gets bigger and, even if you produce, it’s a lot harder to stick on teams.”

Costanzo produced the past two seasons with the Bears. Last year, he collected a team-high 17 tackles after he ranked second in that category in 2012 with 11. Still, he spent three months waiting for a free-agent offer before the 49ers signed him in June.

For his part, Skuta is glad the 49ers made that call.

“Unfortunately I had to play against Blake and he was always a thorn in my side out there,” Skuta said. “I felt like anyone that gave me a hard time was a good player, so it’s good we’re on the same team. We didn’t like each other then, but we’re good now.”

It sounds as if Costanzo won’t be good until he earns a spot on the 53-man roster, but he insists he’s not always unhappy during camp. He enjoys playing football, he explained, just not pondering his uncertain future in the sport.

“Oh, I’m not really miserable,” he said. “I just pretend to be miserable. I have fun out there. It’s all this other baloney I don’t like.”