Essentially, the Tigers suggested, Diaz will serve as a option if team officials decide catching prospect Alex Avila needs more time in the Minor Leagues. To that end, Diaz received an invitation to Major League camp.
"We like him," team president/general manager Dave Dombrowski said. "Some of people really like him, a couple of our guys, and think he's a guy that could possibly compete for a job as a backup catcher in Spring Training. We're still in the mode where, I'm sure in Spring Training, we're going to have to sit back and decide which way we want to go with our backup catcher.
"We know who our No. 1 guy is, but does [manager Jim Leyland] want to keep Alex Avila? Has he progressed enough? Will he get enough at-bats? Should we send him out to Triple-A to play? Does [Diaz] fit the hole? But we do feel like he's got the capabilities to do that."
Diaz profiles as a catcher with respectable offense for a reserve role, though not the same kind of offense as Avila. The 26-year-old hit .279 in 41 games with the Pirates last season, adding seven doubles to go with a home run and 19 RBIs. He backed that up with a .262 average over 44 games at Triple-A Indianapolis with three homers and 15 RBIs.
Diaz carries a .301 average over eight Minor League seasons.
His credentials, however, will probably be secondary to the question of Avila's readiness. The 22-year-old closed out his first full professional season by batting .279 (17-for-61) with four doubles, five home runs, 14 RBIs, 10 walks and 18 strikeouts in 29 games with Detroit, making an immediate impression on club officials. However, Dombrowski cautioned Monday that Avila shouldn't be expected to hit that well over a full season, that he'll go through the typical struggles of youth and have to make adjustments.
There's also the question of how much more work Avila needs behind the plate. He didn't begin catching until his junior year at the University of Alabama, a couple years before he went to the Tigers in the 2008 First-Year Player Draft.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.