The Tesla Model S suffers its first recall.

While it may be a painful process, one of the real measures of whether an automaker has made it into the big leagues is when it has to recall some of its products.

And while the announcement by Tesla is miniscule compared to the 2.7 million Jeeps being recalled – or covered by a less “service action” – it’s nonetheless a significant step for the California-based battery-car start-up.

Tesla Motors issued a terse release early this morning announcing it would recall 1,228 of the Model S battery cars it has built during the second quarter due to a defect in the mounting bracket of the rear seat.

“This reduces our confidence that the left hand seat back will be properly retained in the event of a crash,” wrote Tesla founder and Chief Executive Elon Musk in a statement posted to the company website.

According to the National Highway Traffic Safety Administration, a passenger could be seriously injured if a seat were to come loose in a crash.

(Chrysler’s controversial recall turns out to be smaller than NHTSA had demanded. Click Here for the full story.)

Tesla says it believes about 20% of the Model S sedans produced between May 10 and June 8 of this year may have been improperly welded. It plans to inspect all 1,228 vehicles produced during that period and make repairs as and where necessary.

While not nearly as attention-grabbing as the recall faced by rival Fisker Automotive triggered by a cooling system fire, the announcement is nonetheless a bit of a setback for Tesla which began producing the Model S last summer.

The sedan has, until now, received almost universal praise, something that stands out in a nascent battery market plagued with problems. In fact, the Tesla Model S received a near-perfect score following testing by the influential Consumer Reports magazine earlier this year.

(Tesla may offer battery-swap option for Model S. Click Here for the story.)

That has helped drive a surge in demand, first-quarter sales exceeding initial company expectations and helping to fund Tesla’s first-ever profit.

But volumes are still modest, running under 5,000 vehicles per quarter, so the recall will impact about a quarter of Tesla’s total production run for the April – June quarter.

Tesla shares have more than quadrupled over the past year, surging from a low of $25.52 to a $114.90 peak before settling back. Despite the recall, the maker’s shares were up $2.30 in mid-morning trading to $105.69.