Meantime, outfielder Shane Costa was recalled from Triple-A Omaha to take Perez's spot on the 25-man roster.
"Costa was called up because Teahen isn't available," Bell said. "If he's DL'ed, then Costa will stay. If not, then we'll do something else."
If Teahen does have to go on the DL, the Royals likely will add a pitcher to the roster. Because Thursday is an open date, the club has extra time to make a decision.
According to Bell, Perez will miss three to four weeks because of a strained left knee. In effect, that might end Perez's season, because there will be no Minor League clubs active for which he could pitch on rehab. The Royals' schedule ends on Sept. 30.
Teahen suffered a hyperextended left elbow while diving for a ball Saturday night in Oakland. He hasn't played since.
Third time the charm? Costa was brought up from Omaha for the third time this season. In his previous stints with the Royals, he batted .185 (12-for-65) with seven RBIs.
Omaha was another matter for Costa. For the O-Royals, his average in 59 games was .326. At one point, he had reached base via hit, walk and hit by pitch in 46 consecutive games.
That stretch ended Aug. 10 at Memphis, but still going is his streak of reaching base in 37 consecutive home games at Rosenblatt Stadium. All of this data came as something of a surprise to Costa.
"A reporter came up to me and told me about it. I had no clue," he said.
While with the Royals, Costa twice found himself in the unfamiliar role of cleanup batter. For Omaha, he'd become the leadoff hitter, another twist.
"If he threw the first-pitch heater, I was swinging -- most of the time," Costa said. "But I took my share of walks."
Royals rundown: Shortstop Angel Berroa had three hits, including his eighth home run, and raised his average to .306 as Omaha lost a doubleheader to Albuquerque, 5-1 and 8-6, on Tuesday. First baseman Craig Brazell hit his 30th homer. Brandon Duckworth (six innings, one run) and John Thomson (3 1/3 innings, eight runs) each made a rehab start for Omaha. ... Zach Peterson struck out 13, including 11 in succession, for rookie Idaho Falls in a 9-1 win over Billings. The former University of Illinois-Chicago star dropped his ERA to 3.26. Right fielder Wilson Tucker went 5-for-5 with two doubles. ... First baseman Brad McCann (.249) was 4-for-4, but Class A Wilmington lost to Myrtle Beach, 10-8.
Viva Los Royals: A celebration as part of Hispanic Heritage Month, "Via Los Royals" will be held before a game against the New York Yankees on Friday, Sept. 7, at Kauffman Stadium.
The event will feature a pregame concert by Tejano singer Jay Perez and international star Jose Jose. Hometown favorite Las Estrellas also will perform, with comedian Alex Reymundo as the emcee. LatinPointe is executive producer.
The show will start at 5:30 p.m. CT inside Gate A at the stadium. Fans can meet the entertainers from 7:30 to 8:15 p.m. at the Gate A spiral ramp. After the game, the Royals will have a special edition fireworks display.
A portion of each ticket (up to $8 per ticket sold) purchased through the Group Sales Hispanic Heritage Night program will benefit the Guadalupe Center. "Viva Los Royals" T-shirts will be sold for $10 with proceeds also going to the Guadalupe Center.
Discounted tickets are available by calling 816-504-4040 and selecting the "Group Sales" option.
Coming up: The Royals have an open date on Thursday. They open a three-game series against the Cleveland Indians at 7:10 p.m. CT on Friday at Kauffman Stadium. Zack Greinke will start for the Royals against Indians lefty C.C. Sabathia.