The 6-1 Cook left St. John's after his freshman season and was a 2001 second-round pick of Denver. However, he wanted a two-year contract and was cut in training camp, losing the final point guard spot to fellow rookie Kenny Satterfield.
Cook was placed on the injured list with tendinitis in his left knee. Once active, he will assume the role of Martin, who was the Mavericks' third point guard behind Steve Nash and Tim Hardaway.
The 5-11 Martin, 30, missed all 10 shots and scored only one point in three games with the Mavs. He also has played for the Los Angeles Clippers and Sacramento and was signed as a free agent during the offseason.
Eschmeyer went on the injured list November 8 with a sprained left ankle. The 6-11 center was off to a slow start in his first season with Dallas, collecting just two points and six rebounds in three games.
Eschmeyer spent two seasons with the New Jersey Nets before signing a six-year, $34 million contract as a free agent during the offseason. He was expected to back up Shawn Bradley, but the Mavs have been using Dirk Nowitzki at center, which has limited Eschmeyer's minutes.