Welcome to "MLB Corner," our periodical look at the current season, complete with knee-jerk reactions, and usually a list or two

This week's corner will list the top 5 prospects likely to be called up and have the biggest impacts on their parent clubs from here on out.

Not every rookie call up will be put into a playoff race, but with two wild card berths in each league teams are having trouble evaluating whether or not they are contenders.

Currently there are only two teams, Houston and Tampa, more than 7 games out of the wild card race in the AL due to injury and rebuilding. That number jumps to five in the NL with the Mets and Marlins headed in that direction. That leaves fifteen teams or exactly half the squads in the league, after the 6 division champions, left to chase the wildcards. Leaving Gregory Polanco and George Springer off this list seems right since they have been up and running for some time now.

1.Taijuan Walker | Seattle SP- Walker has been has been highly touted since he was picked in the first round a couple years ago. He made three starts in September last season but didn't look dominant. This year he has battled injuries to make his first start just this week. He has the stuff to overpower hitters and could be ready to take that next developmental step the 2nd half of the season. In case you didn't know, the Mariners currently hold one of the wildcard berths in the AL. Reinforcements for King Felix can't come soon enough, although many pundits have the M's panned for offensive help with their young pitching as trade bait come deadline time.

2.Oscar Taveras | St. Louis OF- Another highly touted prospect that has been up already due to injury but didn't hit enough to stick. Well he's back up, and like Walker needs to start cashing some of that potential. He has been called back up by the red birds due to incumbent Allen Craig struggling at the plate. Scouts and player evaluator types love his all around game, and given his defensive capability can be counted on by manager Mike Matheny in late inning situations. You get the feeling that Taveras just needs that one game where his confidence can take over and not press. The Cards need him to make an impact as they are battling with 5 teams for 3 post season spots all within 2 games.

3.Jimmy Nelson | Milwaukee SP- Nobody saw this season coming from the Brew crew and the front office is looking to hold onto their playoff ticket. Fifth starter Marco Estrada isn't having a very easy time every time out as evidenced by his era north of 5. Nelson most certainly will be called up at the very least as the long man or situational reliever in an effort to monitor his innings total. He is a 6'5” work horse, which the Marlins can tell you from his only big league start earlier this year. At this point he is simply refining his game at the AAA level and can be expected to join the Brewers at the first sign of trouble from the pitching staff.

4.Joc Pederson | LAD OF- The Dodgers struck baseball gold last year when they called up Yasiel Puig. This year Pederson could be that guy for a team that is starting to play up to their potential as of late. They are currently tied for the division lead with the scuffling Giants so there is no real rush on his timetable. The presence of Andre Ethier and his hefty contract make Pederson's arrival murky right now, but he at least will see time in September with an opportunity to take work from Ethier, or Matt Kemp who hasn't been the same since his MVP runner up season three years ago. With a .320 average through 70+ games at AAA he doesn't have much else to prove. Pederson recently suffered a separated shoulder but won't require surgery according to the Dodgers brain trust.

5.Mookie Betts Boston| OF. - The Sox are still in serious World Series hangover mode; they sit 6 games under .500 and their -33 run differential can be attributed to a struggling lineup that Betts has been called upon to fix. He has elite plate discipline that has been on display through two levels of the Red Sox system. Management is hoping his high on base percentage continues at this level to put Big Papi and Dustin Pedroia in RBI opportunities.

All Star game notes to know:

- You Darvish has stated he will not play or attend the game; that's good news for Dallas Keuchel and his 8 wins.

- Giancarlo Stanton will participate in the home Run Derby; that's good news for fans.

- Derek Jeter will be the starter at SS for the AL; that's bad news for Xander Boegarts and his recent ride down the interstate in the batting average department.