Mertesacker's texts brief Arsenal target Podolski
"He has been very interested in the last few weeks and sent me a text message or two," Mertesacker told German Sky Sports News.
"I just responded to him positively, we have a good club here and everyone here has a positive opinion of 'Poldi'."
Podolski's contract with Bundesliga strugglers Cologne does not expire until June 2013, but German media reports claim he has already agreed terms and will join the north London club at the end of the season.
The 26-year-old has made 95 appearances for Germany, is a veteran of two World Cups and was part of the team which reached the Euro 2008 final when the Germans lost to Spain.
"Nothing is fixed yet and Podolski hasn't actually rung me," said Mertesacker, a Germany international who is currently recovering from an ankle ligament operation.
"I think things will happen now behind closed doors."
German daily Bild reported Cologne want 18 million euros (23.7m US dollars) for Podolski, who has scored 16 goals in 20 German league games this season -- more than half of his team's total tally of 31.
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