"Just some minor irritation," team president/general manager Dave Dombrowski said in an email.
The Tigers sent Dirks out on a Minor League rehab assignment a week ago, with a plan to have him spend the full 20 days allowed working his way back into game shape. Essentially, Tigers head athletic trainer Kevin Rand said at the time, that would be Dirks' Spring Training.
Dirks is trying to come back from serious back surgery. What had been lingering back issues over a few years led in March to a microdiscectomy, removing a fragment of disk removing a fragment of disk that tore away from the vertebrae.
Dirks went 5-for-16 with a double and an RBI over six games with Lakeland. He started both ends of a doubleheader on Monday against Port St. Lucie, but was lifted from the second game for a pinch-hitter after two at-bats and two strikeouts. Considering he was the DH in that game, it wasn't simply an issue of rest. Lakeland was off on Tuesday.
No word was immediately available on how long Dirks will be sidelined. Even if it's short, it likely throws another wrench into his timetable. The previous plan put him on track, if everything went well, to be potentially ready around the end of the month. This all but ensures his rehab will at least linger into August.
It also means the Tigers most likely won't get a look at Dirks in the big leagues before the July 31 nonwaiver Trade Deadline. The Tigers have been rumored to be scouting left-handed-hitting outfielders to complement an outfield rotation that currently has four right-handed hitters -- Austin Jackson, Torii Hunter, Rajai Davis and J.D. Martinez.
Dirks, a career .276 hitter over parts of three seasons, played in a career-high 131 games for the Tigers in 2013, batting .256 with nine homers and 37 RBIs.
Jason Beck is a reporter for MLB.com. Read Beck's Blog and follow him on Twitter @beckjason. This story was not subject to the approval of Major League Baseball or its clubs.