Premier League colleagues Cash and Martinez will turn rivals when Poland take on Argentina in Group C on November 30.
Asked if he had been in touch with Martinez ahead of the tournament, Cash told reporters on Saturday: "No bets. I asked him for Messi's shirt, if that's possible.
"Obviously when we step on the pitch, we become rivals although we are teammates at Villa. It's another massive game against a really strong opponent."
In Qatar, English-born defender Cash will play his first major tournament with Poland after being granted citizenship last year.
Cash, who has seven caps for Poland, qualified for citizenship through his mother and grandfather.
"Everybody dreams of playing at a major tournament and it has come now (at the World Cup), which is really exciting," Cash said.
"I really like pressure and think playing in the Premier League is pressure in itself... I want to prove myself on the biggest stage and this is the time to do it."
Poland begin their World Cup campaign on Tuesday against Mexico, whom Cash described as a very strong team.
"Mexico are good but we have to believe we are better," he added. "In our camp, we have to focus on ourselves and get ourselves right."
