Brazil-born Costa, who missed Spain's last two games due to injury, scored in Chelsea's 3-2 Premier League victory at Hull City on Sunday but had to come off with about 15 minutes left due to a hamstring problem.
"Costa will undergo tests on Monday in London and the results will be available to Spain's medical staff for their evaluation," the Spanish football federation (RFEF) said on Spain's official site on Monday.
Juanmi, 21, has represented Spain at junior level and is enjoying a fine season at Malaga, where he has netted seven goals in 24 La Liga appearances, including the winner in a 1-0 success at leaders Barcelona last month.
He will compete for a place up front with Alvaro Morata of Juventus and Barcelona's Pedro. Chelsea midfielder Cesc Fabregas was also named in Del Bosque's squad and could be deployed as a forward.
Juanmi said his selection was recognition for Qatar-owned Malaga, who are seventh with 10 games left and chasing a European qualification berth.
"It's a great honour to be among these (Spain) players who have given us so much," Juanmi said on Malaga's website (www.malagacf.com). "I am determined to enjoy the experience and be available for the coach."
With four matches played, Spain are second in Group C on nine points, three behind leaders Slovakia, who beat them 2-1 in Zilina in October, and level with Ukraine.
They also play a friendly against the Netherlands in Amsterdam on March 31, a repeat of the 2010 World Cup final and the first time the teams will have met since Netherlands crushed Spain 5-1 in the 2014 World Cup group stage.
(Reporting by Iain Rogers, editing by Ken Ferris and Pritha Sarkar)
Share
