That would depend on whether the pitcher is a starter or reliever.
A starting pitcher generally pitches 1 game every 5 days because they pitch a lot of innings each game. Over an MLB season this would mean the #1 starter on a team, over the course of a season where they did not miss a start, would pitch 33-35 games per season. The #1 might get an extra start or two in a season in situations where the team had a day off and the manager decided to go with the #1 starter in a game as opposed to the #5 starter since the #1 had his required number of days of rest. Two of the best starting pitchers in MLB in 2010, Roy Halladay and C.C. Sabathia, pitched in 33 and 34 games, respectively.
A relief pitcher, especially a closer or pitcher that is brought to pitch to only one batter, could pitch in many more games than a starting pitcher because they don't pitch as many innings as a starting pitcher. Two of the best closers in MLB in 2010, Brian Wilson and Rafael Soriano, pitched in 70 and 64 games, respectively. Generally, they pitched only one inning per game.
Two of the best situation pitchers in MLB in 2010, Pedro Feliciano and Randy Choate, pitched in 92 and 85 games, respectively. Feliciano pitched in 62 2/3 innings and Choate pitched in 44 2/3 innings. In many games these guys, both left handers, were brought in to face only one or two hitters who were left handed.
Chat with our AI personalities
There's no rule; theoretically he could start all 162 games if his body would allow it. For the sake of their health and their ability to continue to pitch effectively, though, it's not wise to have them start more than 30-35 games.
An NFL player will play 16 regular season games and 4 or 5 preseason games (most teams play 4 preseason games but the teams that play in the Hall of Fame game play 5). Should his team make the playoffs, he can also play 3 or 4 more games depending on where he team winds up in the Conference rankings and if his team makes it to the Super Bowl. So an NFL player, should he stay healthy and not be injured, would play between 23 and 25 games in a season.